Source: AMERICAN SAMOA COMM COLLEGE submitted to NRP
CANOPY COVER AND WEED MANAGEMENT EFFECTS OF SURVIVAL AND GROWTH OF UNDERPLANTED HARDWOOD TREES IN AN AMERICAN SAMOA FOREST PLANTATION.
Sponsoring Institution
National Institute of Food and Agriculture
Project Status
COMPLETE
Funding Source
MCINTIRE-STENNIS
Reporting Frequency
Annual
Accession No.
0198566
Grant No.
(N/A)
Cumulative Award Amt.
(N/A)
Proposal No.
(N/A)
Multistate No.
(N/A)
Project Start Date
Oct 1, 2003
Project End Date
Dec 31, 2006
Grant Year
(N/A)
Program Code
[(N/A)]- (N/A)
Recipient Organization
AMERICAN SAMOA COMM COLLEGE
(N/A)
PAGO PAGO,AS 96799
Performing Department
EXPERIMENT STATION
Non Technical Summary
American Samoa's forest are being degraded through anthropogenic and natural disturbances, and are frequently unable to regenerate because of invasive species. This project will provide guidelines on shade requirements/tolerances and vegetation management tactics for those wishing to conduct reforestation efforts in American Samoa, including, the National Park of American Samoa, Natural Resource Conservation Service, and private land holders.
Animal Health Component
100%
Research Effort Categories
Basic
(N/A)
Applied
100%
Developmental
(N/A)
Classification

Knowledge Area (KA)Subject of Investigation (SOI)Field of Science (FOS)Percent
1230640107075%
1230640114025%
Knowledge Area
123 - Management and Sustainability of Forest Resources;

Subject Of Investigation
0640 - Tropical forests;

Field Of Science
1070 - Ecology; 1140 - Weed science;
Goals / Objectives
The goal of this research project is to assess the effects of canopy cover on seedling survival and growth and determine the vegetation management requirements in stand restocking of young native Samona hardwoods. The research objectives are to: 1) test the effects of underplanting in various levels of existing canopy cover on seedling establishment and growth, 2) test the effect of polyethylene mulch used for weed control on seedling establishment and growth, and 3) compare the effects of this mulch with hand weeding of a similar-sized area.
Project Methods
Seedlings of eight Samoan hardwood trees, Calophyllum neo-ebudicum, Diospyros samoensis, Flueggea flexulosa, Intsia bijuga, Planchonella samoensis, Pometia pinnata, Syzygium inophylloides, Terminalia richii, will be propagated in the ASCC Land Grant Extension Forestry greenhouse and raised to a height of 30 to 40 cm. Propagation will require seed collection. Transplants may have to be produced by collecting wild seedlings. Seedlings will be transplanted into an existing reforestation study in the Malaeimi Valley, Tutuila, AS, in a random manner. Half of the trees will receive a 1 sq. m polyethylene mulch at the time of planting. The tree will be planted first. Then the mulch is installed over the top of it, inserting the tree through a precut incision in the center of the mulch. The mulch with then be staked to the ground with 15 cm wire staples. Half of the trees will also receive monthly weeding beginning at the time of planting. A 1 sq. m planting area will be scalped and the tree planted in the center of that area. Treatments will be arranged so that one quarter of the trees are mulched, one quarter are weeded, one quarter have both treatments, and the remainder have none-the control. The treatments are intended to provide different forms of vegetation control. Hand weeding will provide through vegetation control of limited duration. Mulching will provide long-term consistent control of ground based vegetation but may not be effective in controlling climbers. The combined treatment will provide the best vegetation control but require a greater investment of resources. A variety of measurements will be taken during this project. Tree height and diameter at 15 cm will be measured at the time of planting, the trees tagged, and diameter measurement points marked with tree paint. Diameter is measured initially at 15 cm to avoid inflated values do to ground level stem swelling. Canopy cover will also be assessed at the time of planting using a ceptometer at a height of 0.5 m. Tree size and canopy cover measurements will be conducted annually for the three-year duration of the study. Ceptometer height will be adjusted for annual canopy cover measurement so that the assessment is only of the canopy overtopping the seedling. Diameter-breast-height (defined as 1.37 m) will be measured when trees reach 1.5 m in height. Seedling survival will be assessed at the time of measurement. This experiment will arranged in a completely randomized design. Factors in the study are: tree species; vegetation management treatments including a control, hand weeding, mulching, and combined weeding and mulching; and percent canopy cover. The data will be analyzed using linear regression for size data, either height or diameter (at 15 or 137 cm) in m or mm, respectively and logistic regression for survival by species. Regression lines for each species will be compared to determine whether tree species have similar responses.

Progress 01/01/06 to 12/31/06

Outputs
Research plots were measured in March 2006. Monthly vegetation maintenance continued through July 2006. In August 2006 the landholder denied access to research plots and they have not been visited since. Analysis of data is in progress.

Impacts
This project will allow improvements in the success of reforestation projects by creating species specific growing conditions. This information is presently being employed in a USFS Forest Land Enhancement Program reforestation project. In addition, these results are being used in forestry Extension workshops and outreach.

Publications

  • No publications reported this period


Progress 01/01/05 to 12/31/05

Outputs
Treatments on study site have been maintained monthly by mowing around the weed and mulch-and-weed treatments. Tree seedlings were measured in March and September, 2005. Hemispherical canopy photos were taken in April and are currently being analyzed. Light reading were made in April as well. Analysis of the 6-month seedling growth has begun. This project is beginning to show visible differences in tree seedling response although these differences have not been statistically assessed. Some species, such as Flueggea, Pometia and Terminalia, are responding well to open conditions. Most species are surviving well in the shade. Vegetation management involving mowing seems to improve seedling response over those that are not mown. In the coming year, monthly treatment maintenance will continue. Seedling will be measured again and survival recorded in March and September along with corresponding measurements of canopy cover and light availability. Temperature at the seedling base will also be assessed on a monthly basis.

Impacts
This project will allow improvements in the success of reforestation projects by creating species specific growing conditions. This information is presently being employed in a USFS Forest Land Enhancement Program reforestation project.

Publications

  • No publications reported this period


Progress 01/01/04 to 12/31/04

Outputs
The study site was manually cleared of unwanted vegetation including vines, grasses, cassava, and selected trees by mowing and slashing. Cassava stems were removed from the study site to prevent layering (re-rooting of stems). Other herbaceous vegetation was piled and burned. Individual planting sites were marked and seedlings planted. Each seedling was identified with a coded tag. After planting, polyethylene mulch was installed around the mulch only and mulch-and-weed treatments. Initial seedling size (height and diameter at 15 cm) measured after treatment. Any seedling mortality that occurred within the first month was replaced. Treatments have been maintained monthly mowing around the weed and mulch-and-weed treatments and checking the mulch installation. In the coming year, monthly treatment maintenance will continue. Seedling will be measured again and survival recorded in March and September along with corresponding measurements of canopy cover and light availability. Temperature at the seedling base will also be assessed on a monthly basis

Impacts
This project will have two primary impacts. First, it will provide information about the light conditions required to grow various commercially useful trees on land that would otherwise not be available for economic production. When agricultural plantations are abandoned, trees can be planted for commercial use to derive economic benefit from the land while it is fallow. The species selected in this project have traditionally been used for Samoan craft work and construction. The second impact is that the project will provide information about regenerating forest trees for environmental purposes. Reforestation efforts in areas such as the National Park of American Samoa or those disturbed by hurricanes would befit from a better understanding of how these tree species, most of which are native, respond to differing levels of canopy cover. Even in undisturbed stands, a better understanding of the light requirements of tree seedlings would allow for the acceleration of successional processes in the forest. It will also provide a comparison of the effects of traditional hand weeding to alternative techniques for vegetation management around tree seedlings.

Publications

  • No publications reported this period