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Catalog of Long Term Research Conducted by the Northeastern Research Station

Catalog #22

Seed Rain Study
To determine the total viable seed rain falling over a range of conditions in the northern hardwood forest.
Low to mid elevations (<2500') in White Mountains, NH. 
A wide range of stands representing different conditions of species, proportion of species and 3 age classes (early stand seed production, intermediate, and mature) will be studied to determine the effects of these independent variables on total seed rain. Seed will be collected, identified, and tested for viability. Stands were well stocked to fully stocked with typical northern hardwoods of NH.
20 randomly sampled points replicated twice
Each point of seed collection was in a >or = 1-hectare uniform stand. Points distributed along: species, species density: 1) early stand seed production, 2) intermediate stand seed production, 3) mature stand seed production. The age varies according to the species under study: pin cherry, paper birch, red maple, white ash, yellow birch, sugar maple, and beech.
Seeds were collected, identified and tested for viability.
Seed rain was caught in seed-collecting devices in each species-species, density-age condition. 
Warm Season Sampling: 20 cylinders 17.5 cm tall and 15.5 cm indiameter were placed ~10 cm above the forest floor and were emptied at 2-week intervals.
Winter Season Sampling: 20 modified cylinders were placed 2 m above snowpack and were emptied at 2-month intervals.
Independent: Total number of seeds by species caught in each stand as determined by cutting test and/or germination test.

Dependent: Species, 
Species diversity: high, 30% to 50%; low 10 to 20% of the stand basal area. (B.A. will be determined with a prism). 
Age: measured by increment borings. 
Other sources of variation include growing site, stand density, elevation, and aspect.

Total number of seeds by species caught in each stand, total number of viable seeds by species in each stand, stand as determined by cutting test and/or germination test: 1981 (11 years from 1976 to 1986).

These (independent variable) conditions will be controlled primarily by selecting representative conditions, avoiding extreme conditions. Samples will be taken in stands only on those till sites where northern hardwoods are well adapted and self reproducing.
Data on tally sheets. Summaries on paper. 
Studies of Ecosystem Processes 
Study plan. 1976. R.E. Graber. 
The above are office reports of U.S. Department of Agriculture, Forest Service, Northeastern Forest Experiment Station, Durham, NH.
William Leak, USDA Forest Service, P.O. Box 640, Durham NH 03824. (603) 868-7655



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