Treesearch

The Sudden Oak Death Sixth Science Symposium provided a forum for current research on sudden oak death, caused by the exotic quarantine pathogen Phytophthora ramorum. More than 50 submissions describing papers or posters on the following sudden oak death/P. ramorum topics are included: biology, genetics, nursery and wildland management, monitoring, and ecology. Abstracts are also provided from a special session on Phytophthoras in California native plant nurseries and restoration sites.

In many parts of North America, ash (Fraxinus) stands have been reduced by the emerald ash borer (Agrilus planipennis) invasion to a few surviving mature trees, saplings, basal sprouts, and seedlings. Without a soil seed bank for Fraxinus spp., tree recovery will require survival and maturation of these younger cohorts to reproductive age. Here we report and analyze the population dynamics of emerald ash borer and its associated natural enemies in ash saplings (2.5–5.8 cm DBH) in six deciduous forest stands in southern Michigan. At these sites, the outbreak population of the pest collapsed...

The degraded stand pictured in this 1955 USDA Forest Service photograph from Maine was dominated by balsam fir (Abies balsamea), red maple (Acer rubrum), paper birch (Betula papyrifera), and American beech (Fagus grandifolia). Stands such as these were typical of second-growth, lowland spruce–fir (Picea–Abies) forests in the Northeast following repeated high grading in the 1800s and early 1900s (Judd 1997). In light of concerns about the sustainability of the eastern spruce–fir cover type, the Forest Service began researching these forests in 1926 at the 1,863-acre Gale River Experimental...

This resource update provides an overview of forest resources in Michigan based on inventories conducted by the U.S. Forest Service, Forest Inventory and Analysis (FIA) program of the Northern Research Station. Estimates are based on field data collected using the FIA annualized sample design and are updated yearly. The annual inventory started in 1999. For the 2016 inventory, estimates for current variables such as area, volume, and biomass are based on 6,662 plot samples collected from 2011 to 2016. Change variables, such as net growth, removals, and mortality, are based on 6,076 samples...

In the eastern United States, American chestnut (Castanea dentata) was historically a major component of forest communities, but was functionally extirpated in the early 20th century by an introduced pathogen, chestnut blight (Cryphonectria parasitica). Because chestnut is fast-growing, long-lived, and resistant to decay, restoration of American chestnut using blight-resistant stock could have the potential to increase carbon sequestration or storage in forested landscapes. However, carbon dynamics are also affected by interspecific competition, succession, natural disturbance, and forest...

Planting trees to mark the passing of events and people is a longstanding tradition around the world. To better understand the contemporary practices of memorialization through planting, we examine living memorials created in response to the events of September 11, 2001. As an extension of the U.S. Forest Service Living Memorials Project, we reviewed existing data (n = 787 sites) and identified 223 sites where stewards mentioned planting 102 kinds of flora. Oaks (Quercus spp.) were most commonly mentioned (17% of sites), while 75% of plants/trees were named at only 1% or fewer sites,...

The Cutting Practice Level study is the longest running study on the Penobscot EF, with over 60 years of continuous measurement data. Studies of this nature provide the unique opportunity to examine long-term forest dynamics and explore outcomes not usually visible on shorter term studies.

As light detection and ranging (LiDAR) technology advances, it has become common for datasets to be acquired at a point density high enough to capture structural information from individual trees. To process these data, an automatic method of isolating individual trees from a LiDAR point cloud is required. Traditional methods for segmenting trees attempt to isolate prominent tree crowns from a canopy height model. We here introduce a novel segmentation method, layer stacking, which slices the entire forest point cloud at 1-m height intervals and isolates trees in each layer. Merging the...

Understanding forest structural changes resulting from postdisturbance management practices such as salvage logging is critical for predicting forest recovery and developing appropriate management strategies. In 2013, a tornado and subsequent salvage operations in northern Maine, USA, created three conditions (i.e., treatments) with contrasting forest structure: blowdown, blowdown + salvage, and control (undisturbed). We sampled forest structure in five stands representing each of these three treatments. Our results document obvious and predictable changes to forest structure caused by the...