Performing Department
Natural Resources
Non Technical Summary
Removal of wood from the forest floor will likely have far-reaching impacts on biodiversity, forest productivity, and ecosystem health and resilience. Even in carefully harvested forest stands, the combined negative effects of canopy reduction, extreme climate, and poor understory regeneration will be compounded by bare and exposed ground devoid of wood. In northern forests, downed woody materials often are used by industry for pellets, mulch and pulp; by small-scale commercial firewood operations; and by households. Collection of wood, usually after a harvest, is perceived as added value or an efficient use of labor and available resources. Yet, woody material left in place can greatly influence forest floor environmental conditions and, through a series of bottom-up processes, can shape community structure and improve forest regeneration. Our studies have demonstrated that woody materials on the ground can buffer temperature extremes, retain moisture during droughts, and benefit many forest animals and plants. With predicted changes in climate, including extreme heat and droughts, excessive removal of wood from the forests could threaten future productivity, increase vulnerability to disease and invasives, and result in a loss of vital ecosystem services. Currently, regeneration in the majority of northern forests is poor for a variety of reasons. We propose to develop practical methods to use wood on the forest floor to increase biodiversity, buffer climate extremes, and improve community structure, seedling establishment and growth to encourage future regeneration.
Animal Health Component
0%
Research Effort Categories
Basic
50%
Applied
50%
Developmental
(N/A)
Goals / Objectives
The overarching objective is to develop practical methods that strike a balance between maintaining long-term forest health and successful regeneration, while allowing for the provision of resources and economic services. Specifically, we will test a simple solution: placement of loosely consolidated piles of treetops and branches on the forest floor, distributed across forest stands. During a timber harvest, the decision of how much wood to remove and the best manner to retain it has long-term implications for sustained forest health, ecology, and economic functions. After a canopy thinning, bare and exposed ground creates poor conditions for regeneration and is slow to recover. We aim to measure the impacts of constructed piles on key environmental and biological factors along a chronological gradient from 0 to 10 years after establishment. The goal is to provide guidelines to forestland owners to encourage straightforward activities that promote regeneration and sustain healthy forests in a changing climate.
Project Methods
The experimental design will include the measurement and monitoring of key environmental and biological processes through time within numerous piles of loosely consolidated treetops in harvested forest stands in the central New York region. Two age groups will be established: forest stands that have been harvested with piles from 0-5 years old and and those from 5-10 years old. In 4 stands, 10 to 20 older piles will be selected from several hundred that were constructed in previous studies. In up to 6 other stands, 10- 20 piles will be selected or created during the course of ongoing harvesting activities. All selected piles will be initially inventoried and then monitored over a 3-year study period. All individual piles, both established and newly constructed, will measure roughly 4 m or more in diameter, and will be paired with a nearby site of equal area in open patches not covered with downed wood. All measurements will be the same within the piles and their paired adjacent open plots. The overall paired sampling design will be the basis for all analyses and comparisons, determining the effects of woody material on measures of health and regeneration potential. Measures will include continuous recordings of ground temperature and soil moisture throughout 3 consecutive growing seasons using individual data loggers. Biological measures will include surveys of species composition and abundance of salamanders, soil macro-invertebrates, fungi, wildflowers, and tree seedlings, from newly germinated plants, to a height of 5 m. Comparative metrics will include measures of species richness, community overlap, and diversity index values. Because we have found that piles of treetops and branches greatly reduce browsing by excluding deer, an important additional measure will be the extent of deer browse on seedlings. In addition we will measure soil microbial respiration as a primary indicator of bacterial and fungal activity - a major source of nutrient release and a key indicator of forest soil health and suitability for tree growth. As a complement, we will use litter bags on the soil surface to measure decomposition rates. We also will tag and measure seedlings of common tree species to measure and compare individual growth rates and survivorship over time within, and in the absence of, woody material. To test if woody piles serve as pools of organic matter we will measure net inputs by measuring the organic layer depth and by using litter traps. All told, the combination of different ecological response variables within the framework of the paired sampling scheme will enable us to test whether the retention of treetops and branches on the forest floor after a harvest can effectively create refuges or clusters of biodiversity, and create pools of nutrients and seedlings to provide the basis for a productive future forest.