Progress 10/01/15 to 09/30/19
Outputs
Target Audience:We reached between six and ten professionals in the invasive plant management field, including representatives from four state agencies, by attending two to five meetings of the New Hampshire Invasive Species Committee in each of the four years of the project (10/2015-9/2019). During each meeting the ecology, management, and regulation of invasive plants, frequently including glossy buckthorn, were discussed and decisions were made about invasive plants to place on the state's 'prohibited' list. ? On August 30, 2019, at the Seacoast Science Center in Rye, NH, we delivered a 45 minute presentation entitled "The Ecology of Invasive Plants" to 30 professionals of the New Hampshire Association of Natural Resource Scientists. Changes/Problems:Our Objective 3, "Examine the relationship between the buckthorn abundance and pine seedling growth", was the only one of the five objectives we did not complete. There were two reasons for this. First, we had shown in previous work, now published, that high density of buckthorn was associated with low density and stem height of eastern white pine. We had planned to show this relationship more precisely under the current project but we came to realize that our planned research would not go far enough beyond the original work to justify the time and effort required. . Second, conversations with managers and landowners convinced us that objectives 1, 2, 4, and 5 should have much higher priority than objective three. What opportunities for training and professional development has the project provided?TRAINING: Information about buckthorn impacts on forests and methods of buckthorn control was presented to two University of New Hampshire undergraduate courses (Forest Ecology, fall semesters of 2016, 2017, 2018; Community Ecology, spring semesters of 2016 and 2018), reaching 199 undergraduate students. Both classes included field visits to forested sites where invasive buckthorn was having impact or was being controlled, and field activities were followed up by written student reports. I served as primary advisor for over 30 undergraduates. I was primary advisor for two master's students, Nicholas Lanzer and Hayley Bibaud, both of whom studied the ecology and control of glossy buckthorn; and one doctoral student, Michael J. Simmons who worked as a research assistant on the ecology and control of invasive glossy buckthorn during the summers of 2016 and 2017. Both master's students have graduated. Four undergraduate students were summer or academic year employees working on this project. Ryan Chiesa, Cody Symonds, Hanna McCarthy, and Jenna O'del learned buckthorn research methods as well as techniques of buckthorn control while working on the buckthorn-pine competition experiment and the buckthorn clipping experiment. Three of these undergraduates have now graduated with baccalaureate degrees. PROFESSIONAL DEVELOPMENT: Information about invasive woody plant management and control in forests was presented to > 50 members of the New Hampshire Timberland Owners Association (NHTOA) during their annual meeting on 14 May 2016 and approximately 25 farmers, landowners, and other members of the interested public at a UNH Agricultural Experiment Station Twilight Meeting on 28 September 2016. On each of two occasions, July 17-18, 2017, and May 16-17, 2018, we informed over 50 forestry professionals about invasive glossy buckthorn invasion, control, and relation to silviculture, in a lecture and field site visit as part of the pine-oak-hemlock module of the Northeast Silviculture Institute for Foresters, "a graduate level program for practicing private and public foresters". The Institute was held in southeastern New Hampshire and west central Maine. We discussed glossy buckthorn control options based on our research with three professional foresters on a visit to the Trescott Lands (public water supply watershed property), Hanover, NH, on September 8. On February 22, 2018, as part of the New Hampshire Invasive Plant Forum in Concord New Hampshire (sponsored by NH Cooperative Extension), we presented a summary of research conducted under this McIntire Stennis project to over 30 professionals in invasive plant management. A consequence of the forum was the New Hampshire Invasives Academy, in which we have participated twice. On each of two occasions, September 27, 2018 (Rye, NH), and again on September 26, 2019 (Mascoma, NH), we delivered a 45 minute presentation entitled "The Ecology of Invasive Plants" to 40 volunteers and professionals - all with interests in invasive plants - enrolled in the Academy. The Academy was run by New Hampshire Cooperative Extension. On August 30, 2019, at the Seacoast Science Center in Rye, NH, we delivered a 45-minute presentation entitled "The Ecology of Invasive Plants" to 30 professionals of the New Hampshire Association of Natural Resource Scientists. How have the results been disseminated to communities of interest?We disseminated information about our project though (1) service on the State's Invasive Species Committee, (2) publications, (3) formal and informal presentations to natural resource professionals, citizen volunteers, and the public, (4) presentations to university and primary school classes. (1) State Committee: We disseminated information to invasive plant managers by serving on the State of New Hampshire Invasive Species Committee (2-5 meetings per year during the reporting period). (2) Publications: We worked with two University of New Hampshire (UNH) Cooperative Extension specialists to write a Forestry Field Note "What we know about glossy buckthorn" which was aimed at the New Hampshire forestry community (landowners, loggers, foresters, forest scientists). It was released on February 16, 2016. We were co-authors on three, peer reviewed, scientific papers published on Forests (2016), Forest Ecology and Management (2017) and Ecological Modelling (2019). These were written to inform other scientists of our findings. (3) Presentations: We disseminated information to the public, conservation volunteers, and professionals by contributing a glossy buckthorn - pine competition display to the UNH Agricultural Experiment Station's exhibit at the New Hampshire Farm and Forest Exposition, January 21-23, 2016. We gave presentations to landowners and practitioners of the New Hampshire Timberland Owners Association (NHTOA) during their annual meeting on 14 May 2016 and members of the interested public at a UNH Agricultural Experiment Station Twilight Meeting on 28 September 2016. On each of two occasions, July 17-18, 2017, and May 16-17, 2018, we informed over 50 forestry professionals about invasive glossy buckthorn invasion, control, and relation to silviculture in a lecture and field site visit as part of the pine-oak-hemlock module of the Northeast Silviculture Institute for Foresters, "a graduate level program for practicing private and public foresters". The Institute was held in southeastern New Hampshire and west central Maine. On February 22, 2018, as part of the New Hampshire Invasive Plant Forum in Concord New Hampshire (sponsored by NH Cooperative Extension), we presented a summary of research conducted under this McIntire Stennis project to over 30 professionals in invasive plant management. A consequence of the forum was the New Hampshire Invasives Academy, in which we have participated twice. On each of two occasions, September 27, 2018 (Rye, NH), and again on September 26, 2019 (Mascoma, NH), we delivered a 45 minute presentation entitled "The Ecology of Invasive Plants" to 40 volunteers and professionals enrolled in the Academy. The Academy was run by New Hampshire Cooperative Extension. We discussed glossy buckthorn control options based on our research with three professional foresters on a visit to the Trescott Lands (public water supply watershed property), Hanover, NH, on September 8. (4) University and primary school activities: On each of two occasions, as part of the University of New Hampshire Undergraduate Research Conferences on April 22, 2017, and April 21, 2018, we presented a poster to over 100 students, faculty, staff, and members of the general public. We presented a slide show on invasive plants to over 100 fifth grade students in the Oyster River School District on December 6th 2017 at the Great Bay Discovery Center. We reached 199 undergraduate University of New Hampshire students in three UNH Forest Ecology classes and two Community Ecology classes. These students collected field data and wrote a scientific paper about glossy buckthorn ecology and management. What do you plan to do during the next reporting period to accomplish the goals?
Nothing Reported
Impacts
What was accomplished under these goals?
IMPACT: Over 20, woody non-native species, including glossy buckthorn, invade native forests of the eastern USA. Initial studies indicate that these exotic plants inhibit the growth of regenerating seedlings and saplings of economically important native trees, especially eastern white pine. Precise measurement of these inhibitory effects will allow more effective targeting and prioritization of control efforts, and development of simple, cost-effective control measures should allow inhibitory effects to be minimized. Objective 1. Test the effectiveness of manual control of glossy buckthorn in logged, white pine forests. We tested the effects of repeated manual cutting of buckthorn stems (second year plants) at different stem heights. Two to three cuts (at 21 or 28 day intervals) at the stem base (i.e., ground surface) resulted in 100% buckthorn mortality. Cutting at heights greater than 5 cm (2 inches) above the stem base, however, resulted in no buckthorn mortality and most of these plants actually increased biomass production with time. The same cutting treatments done on 7-8 year old plants in natural populations revealed that over 6 or more cuts at the stem base were required to achieve 90% mortality. A controlled experiment using basal cutting at 21 day intervals on 1-, 2-, 3-, and 4-year old plants showed that a greater number of cuts was required to kill older plants. For 1-year old plants, stems cut at 5 cm and above could be killed if all new stem and butt sprouts, even those below the cutting height, were removed at each cut cycle. Objective 2. See if buckthorn control increases the growth of white pine seedlings. We maintained an experiment in which white pine seedlings were exposed to competition with glossy buckthorn plants of the same age. Over four years, buckthorn grew faster than pine, and pine growing with buckthorn showed reduced height, stem diameter, and crown width compared to buckthorn-free controls. After four years, buckthorn plants were 2 meters (6.5 feet) tall, greatly overtopping pine which rarely exceeded 0.6 meters (two feet). Pine growing with buckthorn showed reduced growth compared to controls (which experienced no competition), although pine mortality was not affected by buckthorn. Objective 3. Examine the relationship between the buckthorn abundance and pine seedling growth. We did not work on this objective over the course of this project. We had shown in previous work, now published, that high density of buckthorn was associated with low density and stem height of eastern white pine. Objectives 1, 2, 4, and 5, were given higher priority and so our efforts were focused on them. Objective 4. Test the effectiveness of planted grass turfs in reducing buckthorn abundance. We collected data from an experiment in which buckthorn seeds and seeds of eastern white pine were sown into plots on tilled agricultural soils that were treated in five different ways: planted grass turf, compacted soil, oak leaf litter, pine leaf little, no treatment (control). Grass turf and pine litter significantly reduced buckthorn emergence from sown seed but only grass turf reduced buckthorn survival. After two growing seasons buckthorn was nearly eliminated from grass turf and none of the few remaining plants in that treatment flowered or produced seed. In all other treatments buckthorn had nearly 100% survival in year two and at least some plants produced flowers and seeds. Objective 5. Examine the importance of glossy buckthornin forests over successional time testing the hypothesis that it is unlikely to persist in older stands. We studied the relationship between buckthorn abundance and stand age using 20 hemlock-pine-hardwood stands that varied in the year of agricultural abandonment. Buckthorn was absent in stands > 150 years old and declined with both stand age and the abundance of shade tolerant tree species. We infer that buckthorn declines with forest succession. We examined the colonization by glossy buckthorn of naturally-occurring canopy gaps in a mature, late-successional hemlock-hardwood forest. Buckthorn was more abundant in canopy gaps than under closed canopy and buckthorn survival was greater in gaps. Even in gaps > 10 years old, however, buckthorn remained small (< 0.5 m in height) and non-reproductive, suggesting that the buckthorn population in this forest is not self-sustaining but dependent on seeds from source plants outside the stand. Seedling survival increased with age, with almost 100% mortality of first year seedlings and seedlings > 1 year surviving at better than 25%. Height growth was 0-5 cm per year and no buckthorn plants reproduced, suggesting that the buckthorn population in this forest is not self-sustaining but rather dependent on seeds from source plants outside the stand. CHANGE IN KNOWLEDGE: We have established the importance of height of stem cutting in buckthorn control. The common practice of manually cutting buckthorn stems at 8 inches or more above the ground surface does not kill buckthorn. Buckthorn death is only likely if stems are repeatedly cut at ground level, but the effectiveness of this treatment is reduced as plants age. Thus, repeated basal cutting can be used to control younger buckthorn but perhaps not older plants (unless an excessive number of cuttings is used). This finding can be applied to improve buckthorn control, at least early in the invasive process. That establishment of glossy buckthorn from seed can be reduced with grass turf is new information that can be used to reduce buckthorn establishment in log landings, skid roads, or other areas impacted by logging. We also found that glossy buckthorn abundance declines over successional time (with stand age and with increased abundance of shade tolerance trees) and that it is absent in very old stands. This means that in mature stands not undergoing management buckthorn may decline naturally without expensive, active control by the landowner. Our initial work on canopy gaps suggests that buckthorn cannot form self-sustaining populations in mature hemlock-hardwood stands experiencing natural disturbance regimes.
Publications
- Type:
Journal Articles
Status:
Published
Year Published:
2019
Citation:
Szewczyk, T.M., Lee, M.J. Ducey, M.E. Aiello-Lammens, H. Bibaud, M.Allen. 2019. Local management in a regional context: Simulations with process-based species distribution models. Ecological Modelling 413:108827. https://doi.org/10.1016/j.ecolmodel.2019.108827
- Type:
Theses/Dissertations
Status:
Published
Year Published:
2019
Citation:
Bibaud, Hayley. 2019. Factors limiting the success of invasive glossy buckthorn (Frangula alnus) in New Hampshires eastern white pine hardwood forests. Master of Science thesis, University of New Hampshire.
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Progress 10/01/17 to 09/30/18
Outputs
Target Audience:We reached between six and ten professionals in the invasive plant management field by attending five meetings of the New Hampshire Invasive Species Committee on October 26, 2017; December 5, 2017; March 15, 2018; and April 11, 2018. Ecology and control of invasive plants, including glossy buckthorn, were discussed at these meetings. We presented a slide show on invasive plants to over 100 fifth grade students in the Oyster River School District on December 6th 2017 at the Great Bay Discovery Center. On February 22, 2018, as part of the New Hampshire Invasive Plant Forum in Concord New Hampshire (sponsored by NH Cooperative Extension), we presented a summary of research conducted under this McIntire Stennis project to over 30 professional in invasive plant management. As part of the University of New Hampshire Undergraduate Research Conference, April 21, 2018, we presented a poster to over 100 students, faculty, staff, and members of the general public. On May 16-17, 2018, we informed over 50 forestry professionals about invasive glossy buckthorn invasion, control, and relation to silviculture in a lecture and field site visit as part of the pine-oak-hemlock module of the Northeast Silviculture Institute for Foresters, "a graduate level program for practicing private and public foresters" sponsored by the US Forest Service. The Institute took place in southeastern New Hampshire. We reached 50 undergraduate students in the UNH Forest Ecology class in August and September 2018. These students visited a forested site where buckthorn had become abundant, were involved in buckthorn removal at that site, and wrote a scientific paper about the colonization, population dynamics,and persistence of buckthorn in New Hampshire forests. On September 27, 2018, we delivered a 45-minute presentation to 40 volunteers and professionals interested in the control of invasive plants at the New Hampshire Invasives Academy on "The Ecology of Invasive Plants". The Academy was run by New Hampshire Cooperative Extension. Changes/Problems:
Nothing Reported
What opportunities for training and professional development has the project provided?TRAINING: Information about buckthorn impacts on forests and methods of buckthorn control was presented to two University of New Hampshire undergraduate courses (Forest Ecology, fall 2018; Conservation Biology, spring 2018), reaching over 80 undergraduate students. The Forest Ecology course ((NR 527), 50 students) took field visits to forested sites where invasive buckthorn was having impact or was being controlled, and students wrote reports about their research on buckthorn. We served on the advisory committees of four graduate students working on invasive plant ecology for their master of science research (Randy Shoe, Katie Moran, Chad Hammer, Mitch O'Neill). I served as primary academic advisor for over 20 undergraduates, four of whom were graduating seniors. I was primary advisor for one master-of-science student, Hayley Bibaud, whose thesis research focuses on invasive glossy buckthorn in forests (objective 5). Two undergraduate student employees, Hannah McCarthy and Jenna O'del, learned buckthorn research methods as well as techniques of buckthorn control while working on the buckthorn in gaps project and the buckthorn clipping experiment. PROFESSIONAL DEVELOPMENT: We informed over 50 forestry professionals about invasive glossy buckthorn invasion, control, and relation to silviculture, in a lecture and field site visit as part of the pine-oak-hemlock module of the Northeast Silviculture Institute for Foresters, "a graduate level program for practicing private and public foresters", run on May 16=17, 2018, in New Hampshire. On September 27, 2018, we delivered a slide presentation to 40 volunteers and professionals interested in the control of invasive plants at the New Hampshire Invasives Academy run by New Hampshire Cooperative Extension. How have the results been disseminated to communities of interest?We disseminated information to invasive plant managers by serving on the State of New Hampshire Invasive Species Committee (attended five meetings during the reporting period). We also informed over 50 forestry professionals about invasive glossy buckthorn invasion, control, and relation to silviculture, in a lecture and field site visit as part of the pine-oak-hemlock module of the Northeast Silviculture Institute for Foresters, "a graduate level program for practicing private and public foresters", run on July 17-18 in New Hampshire. On September 27, 2018, we delivered a slide presentation to 40 volunteers and professionals interested in the control of invasive plants at the New Hampshire Invasives Academy run by New Hampshire Cooperative Extension. What do you plan to do during the next reporting period to accomplish the goals?Objectives 1 and 2. In the fourth year of the project, we conduct an experiment to determine the effect of cutting stems at ground level as a function of plant age. We will re-sample the white pine seedlings and buckthorn plants in our long-term buckthorn control experiment (where buckthorn was cut and flamed just prior to the 2010 logging of an infested eastern white pine stand) to assess the success of buckthorn control and pine release. We will maintain and collect data from our buckthorn-pine competition experiment. Objective 3. We will conduct a correlative field study (in post-logging buckthorn thickets) to determine the relationship between the buckthorn abundance and pine seedling growth. Objective 4. We will continue to monitor buckthorn and pine seedling emergence, growth, survival, and reproduction in our newly established (2016) experiment in which buckthorn seeds were sown into plots treated with planted grass turfs, compacted soil, oak leaf litter, pine leaf little, and no treatment. Objective 5. We will write and submit for publication a brief article on our work on buckthorn abundance and forest succession. We will complete our study of colonization of canopy gaps in mature forests by invasive shrubs. Specifically, we will assess the abundance and survival of tagged buckthorn in canopy gaps and non-gap forest understories. We will complete a study of buckthorn abundance in relation to forest canopy species composition.
Impacts
What was accomplished under these goals?
IMPACT: Over 20, woody non-native plant species, including glossy buckthorn, invade native forests of the eastern USA. Some of these exotic plants inhibit the growth of regenerating seedlings and saplings of economically important native trees, including eastern white pine. Precise measurement of these inhibitory effects will allow more effective targeting and prioritization of control efforts, and development of simple, cost-effective control measures should allow inhibitory effects to be minimized. Objective 1. Test the effectiveness of manual control of glossy buckthorn in logged, white pine forests. We tested the effects of repeated manual cutting of buckthorn stems on second-year plants grown from seed and free of competition. There were two treatments: (1) cutting at the stem base (ground level) and (2) cutting just below the first branch (3-12 inches above ground). Every 21 days after these initial treatments we removed all stump and butt sprouts. 100% buckthorn mortality was achieved after three applications. Objective 2. See if buckthorn control increases the growth of white pine seedlings. We maintained an experiment in which white pine seedlings were exposed to competition with glossy buckthorn plants of the same age. The experiment was plagued by high pine mortality, necessitating re-planting of two-year old white pine. After four years, buckthorn plants were 2 meters (6.5 feet) tall, greatly overtopping pine which rarely exceeded 0.6 meters (two feet). Pine growing with buckthorn showed reduced growth compared to controls (which experienced no competition), although pine mortality was not affected by buckthorn. Objective 3. Examine the relationship between the buckthorn abundance and pine seedling growth. We did not work on this objective this year. Objective 4. Test the effectiveness of planted grass turfs in reducing buckthorn abundance. We collected data from an experiment in which buckthorn seeds and seeds of eastern white pine were sown (fall, 2016) into plots on tilled agricultural soils that were treated in five different ways: planted grass turf, compacted soil, oak leaf litter, pine leaf little, no treatment (control). Grass turf and pine litter significantly reduced buckthorn emergence from sown seed but only grass turf reduced buckthorn survival. After two growing seasons buckthorn was nearly eliminated from grass turf and none of the few remaining plants in that treatment flowered or produced seed. In all other treatments, buckthorn had nearly 100% survival in year two and at least some plants produced flowers and seeds. Objective 5. Examine the importance of glossy buckthornin forests over successional time testing the hypothesis that it is unlikely to persist in older stands. We examined the growth and survival of glossy buckthorn in naturally-occurring canopy gaps in a mature hemlock-hardwood forest where buckthorn establishment is infrequent outside of gaps. Seedling survival increased with age, with almost 100% mortality of first-year seedlings and seedlings > 1 year surviving at better than 25%. Height growth was 0-5 cm per year and no plants reproduced, suggesting that the buckthorn population in this forest is not self-sustaining but dependent on seeds from source plants outside the stand. These results are consistent with those of the previous year. CHANGE IN KNOWLEDGE: That establishment of glossy buckthorn from seed can not only be reduced but almost eliminated with planted grass turf is new information. The past year's results suggest inhibitory effects greater than suggested in year one. Buckthorn recruitment from seed in log landings, skid roads, or other areas impacted by logging could be strongly inhibited by timely establishment of grass turfs.
Publications
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Progress 10/01/16 to 09/30/17
Outputs
Target Audience:We reached between six and ten professionals in the invasive plant management field by attending four meetings of the New Hampshire Invasive Species Committee on January 19, February 18, March 16, and April 20, 2017, during which ecology and control of invasive plants, including glossy buckthorn, were discussed. As part of the University of New Hampshire Undergraduate Research Conference, April 22, 2017, an undergraduate student associated with our project presented a poster to over 100 students, faculty, staff, and members of the general public. On June 15, we presented ideas on invasive plant control to a weed control practitioner in an all-day visit to invaded sites in Northfield, VT. We informed over 50 forestry professionals about invasive glossy buckthorn invasion, control, and relation to silviculture, in a lecture and field site visit which were part of the pine-oak-hemlock module of the Northeast Silviculture Institute for Foresters, "a graduate level program for practicing private and public foresters", sponsored by the US Forest Service and NH Cooperative extension and run on July 17-18 in New Hampshire and Maine. We reached 38 undergraduate students in the UNH Forest Ecology class in August and September, 2017. These students visited a forested site where buckthorn had become abundant, were involved in buckthorn removal at that site, and wrote a scientific paper about the colonization, population dynamics and persistence of buckthorn in New Hampshire forests. We discussed glossy buckthorn control options based on our research with three professional foresters on a visit to the Trescott Lands (public water supply watershed property), Hanover, NH, on September 8. Changes/Problems:
Nothing Reported
What opportunities for training and professional development has the project provided?TRAINING: Information about buckthorn impacts on forests and methods of buckthorn control was presented to two University of New Hampshire undergraduate courses (Forest Ecology, fall 2017; Conservation Biology, spring 2017), reaching over 70 undergraduate students. The Forest Ecology course (38 students) also took field visits to forested sites where invasive buckthorn was having impact or was being controlled, and students wrote reports about their research o buckthorn. I served as primary advisor for over 20 undergraduates, twelve of whom were graduating seniors. I was primary advisor for one doctoral student, Michael J. Simmons, who worked as a research assistant on the ecology and control of invasive glossy buckthorn during the summers of 2016 and 2017. I was primary advisor for one new master-of-science student, Hayley Bibaud, whose thesis research focuses on invasive glossy buckthorn in forests. Two undergraduate student employees, Hannah McCarthy and Cody Symonds, learned buckthorn research methods as well as techniques of buckthorn control while working on the buckthorn in gaps project and the buckthorn clipping experiment. PROFESSIONAL DEVELOPMENT: We informed over 50 forestry professionals about invasive glossy buckthorn invasion, control, and relation to silviculture, in a lecture and field site visit as part of the pine-oak-hemlock module of the Northeast Silviculture Institute for Foresters, "a graduate level program for practicing private and public foresters", run on July 17-18 in New Hampshire and Maine. We discussed glossy buckthorn control options based on our research with three professional foresters on a visit to the Trescott Lands (public water supply watershed property), Hanover, NH, on September 8. How have the results been disseminated to communities of interest?We disseminated information to invasive plant managers by serving on the State of New Hampshire Invasive Species Committee (attended at least four meetings during the reporting period). We also informed over 50 forestry professionals about invasive glossy buckthorn invasion, control, and relation to silviculture, in a lecture and field site visit as part of the pine-oak-hemlock module of the Northeast Silviculture Institute for Foresters, "a graduate level program for practicing private and public foresters", run on July 17-18 in New Hampshire and Maine. We discussed glossy buckthorn control options based on our research with three professional foresters on a visit to the Trescott Lands (public water supply watershed property), Hanover, NH, on September 8. What do you plan to do during the next reporting period to accomplish the goals?Objectives 1 and 2. In the third year of the project we will re-sample the white pine seedlings and buckthorn plants in our long-term buckthorn control experiment (where buckthorn was cut and flamed just prior to the 2010 logging of an infested eastern white pine stand) to assess success of buckthorn control and pine release. We will maintain and collect data from our buckthorn-pine competition experiment. We will expand our experiments to test the effect of cutting height of buckthorn stems on survival and growth in older plants in natural conditions. Objective 3. We will initiate a correlative field study (in post-logging buckthorn thickets) to determine the relationship between the buckthorn abundance and pine seedling growth. Objective 4. We will continue to monitor buckthorn and pine seedling emergence, growth, and survival in our newly established (2016) experiment in which buckthorn seeds were sown into plots treated with planted grass turfs, compacted soil, oak leaf litter, pine leaf little, and no treatment. Objective 5. We will write and submit for publication a brief article on our work on buckthorn abundance and forest succession. We will continue our study of colonization of canopy gaps in mature forests by invasive shrubs. Specifically, we will assess abundance and survival of tagged buckthorn in canopy gaps and non-gap forest understories.
Impacts
What was accomplished under these goals?
IMPACT: Over 20, woody non-native species, including glossy buckthorn, invade native forests of the eastern USA. Initial studies indicate that these exotic plants inhibit the growth of regenerating seedlings and saplings of economically important native trees. Precise measurement of these inhibitory effects will allow more effective targeting and prioritization of control efforts, and development of simple, cost-effective control measures should allow inhibitory effects to be minimized. Objective 1. Test the effectiveness of manual control of glossy buckthorn in logged, white pine forests. We tested the effects of repeated manual cutting of buckthorn stems on second year plants grown from seed, free of competition. Two to three cuts (at 28 day intervals) at ground level resulted in 100% buckthorn mortality. Cutting at 5 or 15 cm above ground, however, resulted in little if any buckthorn mortality and most of these plants actually increased biomass production with time. The same cutting treatments done on 7-8 year old plants in natural populations produced very different results, with minimal mortality at all cutting heights. Objective 2. See if buckthorn control increases the growth of white pine seedlings. We maintained an experiment in which white pine seedlings were exposed to competition with glossy buckthorn plants of the same age. The experiment was plagued by high pine mortality in winter 2016-17, necessitating re-planting of two-year old white pine. Over three years, buckthorn grew much faster than pine, and pine growing with buckthorn showed reduced growth compared to controls, although pine mortality rates were not affected by buckthorn. Objective 3. Examine the relationship between the buckthorn abundance and pine seedling growth. We did not work on this objective this year. Objective 4. Test the effectiveness of planted grass turfs in reducing buckthorn abundance. We collected data from an experiment in which buckthorn seeds and seeds of eastern white pine were sown (fall, 2016) into plots treated in five different ways: planted grass turfs, compacted soil, oak leaf litter, pine leaf litter, and no treatment. Preliminary analysis of data indicated that grass turfs, compacted soil, and pine litter all reduced buckthorn recruitment relative to untreated and oak leaf litter treatments, and that turf grass also reduced survival of buckthorn seedlings. Pine seedling recruitment was similarly reduced, although less so than buckthorn on pine needle litter. Objective 5. Examine the importance of glossy buckthornin forests over successional time testing the hypothesis that it is unlikely to persist in older stands. We examined the colonization by glossy buckthorn of naturally-occurring canopy gaps in a mature hemlock-hardwood forest. Buckthorn was more abundant in canopy gaps than under the closed canopy and buckthorn survival was greater in gaps. Even in gaps > 10 years old, however, buckthorn plants remained small (< 0.5 m in height) and were non-reproductive, suggesting that the buckthorn population in this forest is not self-sustaining but rather dependent on seeds from reproductive plants outside the stand. CHANGE IN KNOWLEDGE: We have established the importance of height of stem cutting in buckthorn control. The common practice of manually cutting buckthorn stems at 8 inches or more above the ground surface does not kill buckthorn. Buckthorn death is only likely if stems are repeatedly cut at ground level, and this seems to be true primarily for young buckthorn stems. This finding can be applied to improve buckthorn control, at least early in the invasion process. That establishment of glossy buckthorn from seed can be reduced with grass turf is new information that may be useful in reducing buckthorn establishment in log landings, skid roads, or other areas impacted by logging. Our initial work on canopy gaps suggests that buckthorn cannot form self-sustaining populations in mature hemlock-hardwood stands experiencing natural disturbance regimes.
Publications
- Type:
Journal Articles
Status:
Published
Year Published:
2017
Citation:
Lanzer, N.B., T.D. Lee, M.J. Ducey, S.E. Eisenhaure. 2017. Sapling white pine (Pinus strobus L.) exhibits growth response following selective release from competition with glossy buckthorn (Frangula alnus P. Mill) and associated vegetation. Forest Ecology and Management 404:280-288.
- Type:
Journal Articles
Status:
Published
Year Published:
2016
Citation:
Lee, T.D., S.E. Eisenhaure, I.P. Gaudreau. 2016. Pre-logging treatment of invasive glossy buckthorn (Frangula alnus Mill.) promotes regeneration of eastern white pine (Pinus strobus L.). Forests 8, 16; doi:10.3390/f8010016.
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Progress 10/01/15 to 09/30/16
Outputs
Target Audience:We informed an unknown number of landowners and forestry professionals about invasive glossy buckthorn by contributing display to the UNH Agricultural Experiment Station's exhibit at the New Hampshire Farm and Forest Exposition, January 21-23, 2016. We worked with two University of New Hampshire (UNH) Cooperative Extension specialists to produce a Forestry Field Note "What we know about glossy buckthorn" which was released to the New Hampshire forestry community (landowners, loggers, foresters, forest scientists) on February 16 2016. We presented our findings from buckthorn plantings and clipping experiments to the New Hampshire Timberland Owners Association (NHTOA) during their annual meeting on 14 May 2016. Approximately 50 NHTOA members, mainly forest land owners and natural resource professionals, attended our two presentations. We presented findings from our buckthorn plantings and clipping experiments to approximately 25 farmers, landowners, and other members of the interested public at a UNH Agricultural Experiment Station Twilight Meeting on 28 September 2016. We made site visits to Odiorne Point State Park and UNH Kingman farm on 3 August with New Hampshire Department of Agriculture invasive species specialist Doug Cygan to view and discuss invasive control methods (Odiorne) and our experimental buckthorn work (Kingman Farm).We reached between six and ten professionals in the invasive plant management field by attending two meetings of the New Hampshire Invasive Species Committee (21 January, 18 February), during which ecology and control of invasive plants including glossy buckthorn were discussed. At least 20 natural resource professionals and academic ecologists were introduced to new approaches to buckthorn control during a public thesis defense (Nicholas Lanzer, M.S.) on 8 September 2016. We reached 32 undergraduate students in the UNH Community Ecology class in March-April 2016. These students visited a white pine - hardwoods forest and analyzed the distribution of glossy buckthorn in relation to canopy cover and tree species composition. Students analyzed the data they collected and wrote a paper describing their results and conclusions. We reached 41 undergraduate students in the UNH Forest Ecology class in September, 2016. These students visited a forested site where buckthorn had become abundant, were involved in buckthorn removal at that site, and wrote a scientific paper about the colonization, population dynamics and persistence of buckthorn in New Hampshire forests. Changes/Problems:
Nothing Reported
What opportunities for training and professional development has the project provided?TRAINING: Information about buckthorn impacts on forests and methods of buckthorn control was presented to two University of New Hampshire undergraduate courses (Forest Ecology, fall 2016; Community Ecology, spring 2016), reaching 73 undergraduate students. Both presentations involved field visits to forested sites where invasive buckthorn was having impact or was being controlled, and both presentations were followed up by written student reports. I was primary advisor for one doctoral student, Michael J. Simmons, who worked as a research assistant on the ecology and control of invasive glossy buckthorn during the summer of 2016. I was primary advisor for one master-of-science student, Nicholas Lanzer, whose thesis focused on control of invasive glossy buckthorn in forests. One undergraduate student summer employee, Ryan Chiesa, learned buckthorn research methods as well as techniques of buckthorn control while working on the buckthorn-pine competition experiment and the buckthorn clipping experiment. I served as primary advisor for over 20 undergraduates, six of whom were graduating seniors. PROFESSIONAL DEVELOPMENT: Information about invasive woody plant management and control in forests was presented to over 50 members of the New Hampshire Timberland Owners Association (NHTOA) during their annual meeting on 14 May 2016 and approximately 25 farmers, landowners, and other members of the interested public at a UNH Agricultural Experiment Station Twilight Meeting on 28 September 2016. How have the results been disseminated to communities of interest?We disseminated information to invasive plant managers by serving on the State of New Hampshire Invasive Species Committee (attended three meetings during the reporting period). We contributed a glossy buckthorn - pine competition display to the UNH Agricultural Experiment Station's exhibit at the New Hampshire Farm and Forest Exposition, January 21-23, 2016. We worked with two University of New Hampshire (UNH) Cooperative Extension specialists to write a Forestry Field Note "What we know about glossy buckthorn" which was aimed at the New Hampshire forestry community (landowners, loggers, foresters, forest scientists). It was released on February 16 2016. We gave presentations to the New Hampshire Timberland Owners Association (NHTOA) during their annual meeting on 14 May 2016 and members of the interested public at a UNH Agricultural Experiment Station Twilight Meeting on 28 September 2016. What do you plan to do during the next reporting period to accomplish the goals?Objectives 1 and 2. In the second year of the project we will re-sample the white pine seedlings and buckthorn plants in our long-term buckthorn control experiment (where buckthorn was cut and flamed just prior to the 2010 logging of an infested eastern white pine stand) to assess success of buckthorn control and pine release. We will publish a peer-reviewed, scientific paper about the effectiveness of pre-logging control of buckthorn (the manuscript is in revision). We will maintain and collect data from our buckthorn-pine competition experiment. We will initiate new experiments to test the effect of cutting height of buckthorn stems on survival and growth. Objective 3. We will initiate a correlative field study (in post-logging buckthorn thickets) to determine the relationship between the buckthorn abundance and pine seedling growth. Objective 4. We will closely monitor buckthorn seedling emergence and growth in our newly established (2016) experiment in which buckthorn seeds were sown into plots treated with planted grass turfs, compacted soil, oak leaf litter, pine leaf little, and no treatment. Objective 5. We will write and submit for publication a brief article on our work on buckthorn abundance and forest succession. We will continue our study of colonization of canopy gaps in mature forests by invasive shrubs. Specifically, we will assess abundance and survival of tagged buckthorn in canopy gaps and non-gap forest understories.
Impacts
What was accomplished under these goals?
IMPACT: Over 20, woody non-native species, including glossy buckthorn, invade native forests of the eastern USA. Initial studies indicate that these exotic plants inhibit the growth of regenerating seedlings and saplings of economically important native trees. Precise measurement of these inhibitory effects will allow more effective targeting and prioritization of control efforts, and development of simple, cost-effective control measures should allow inhibitory effects to be minimized. Objective 1. Test the effectiveness of manual control of glossy buckthorn in logged, white pine forests. We tested the effects of repeated manual cutting of buckthorn stems (second year plants) at different stem heights. Two to three cuts (at 28 day intervals) at the ground surface resulted in 100% buckthorn mortality. Cutting buckthorn at 20 cm, however, resulted in no buckthorn mortality and most of these plants actually increased biomass production with time. Objective 2. See if buckthorn control increases the growth of white pine seedlings. We maintained an experiment in which white pine seedlings were exposed to competition with glossy buckthorn plants of the same age. Over two years, buckthorn grew faster than pine, and pine growing with buckthorn showed reduced height, stem diameter, and crown width compared to buckthorn-free controls. Objective 3. Examine the relationship between the buckthorn abundance and pine seedling growth. We did not work on this objective this year. Objective 4. Test the effectiveness of planted grass turfs in reducing buckthorn abundance. We set up an experiment in which buckthorn seeds were sown into plots treated in five different ways: planted grass turfs, compacted soil, oak leaf litter, pine leaf little, no treatment. No data will be available until next year. Objective 5. Examine the importance of glossy buckthornin forests over successional time testing the hypothesis that it is unlikely to persist in older stands. We studied the relationship between buckthorn abundance and stand age using 20 stands that varied in the year of agricultural abandonment. Buckthorn was absent in stands > 150 years old and declined with both stand age and the abundance of shade tolerant tree species. We inferred that buckthorn declines with forest succession. We also examined the colonization by glossy buckthorn of canopy gaps in mature forests. CHANGE IN KNOWLEDGE: We have established the importance of height of stem cutting in buckthorn control. The common practice of manually cutting buckthorn stems at 8 inches or more above the ground surface does not kill buckthorn. Buckthorn death is only likely if stems are repeatedly cut at ground level. This finding can be applied immediately to improve buckthorn control. We also found that glossy buckthorn abundance declines over successional time (with stand age and with increased abundance of shade tolerance trees) and that it is absent in very old stands. This means that in mature stands not undergoing management buckthorn may decline naturally, without expensive, active control by the landowner.
Publications
- Type:
Theses/Dissertations
Status:
Published
Year Published:
2016
Citation:
Lanzer, Nicholas. 2016. Limiting impacts of invasive glossy buckthorn in southeastern New Hampshire woodlands: Studies of intensive control and forest dynamics. Master of Science thesis, University of New Hampshire.
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