Charles H. Perry

Temperature drives global patterns in forest biomass distribution in leaves, stems, and roots

Significance Do forests in cold or dry climate zones distribute more resources in roots to enhance uptake of water and nutrients, which are scarce in such climates? Despite its importance to forest ecology and global carbon cycle modeling, this question is unanswered at present. To answer this question, we compiled and analyzed a large dataset (>6,200 forests, 61 countries) and determined that the proportion of total forest biomass in roots is greater and in foliage is smaller in increasingly cold climates. Surprisingly, allocation to roots or foliage was unrelated to aridity. These findings allow, for the first time to our knowledge, biogeographically explicit mapping of global root carbon pools, which will be useful for assessing climate change impacts on forest carbon dynamics and sequestration. Whether the fraction of total forest biomass distributed in roots, stems, or leaves varies systematically across geographic gradients remains unknown despite its importance for understanding forest ecology and modeling global carbon cycles. It has been hypothesized that plants should maintain proportionally more biomass in the organ that acquires the most limiting resource. Accordingly, we hypothesize greater biomass distribution in roots and less in stems and foliage in increasingly arid climates and in colder environments at high latitudes. Such a strategy would increase uptake of soil water in dry conditions and of soil nutrients in cold soils, where they are at low supply and are less mobile. We use a large global biomass dataset (>6,200 forests from 61 countries, across a 40 °C gradient in mean annual temperature) to address these questions. Climate metrics involving temperature were better predictors of biomass partitioning than those involving moisture availability, because, surprisingly, fractional distribution of biomass to roots or foliage was unrelated to aridity. In contrast, in increasingly cold climates, the proportion of total forest biomass in roots was greater and in foliage was smaller for both angiosperm and gymnosperm forests. These findings support hypotheses about adaptive strategies of forest trees to temperature and provide biogeographically explicit relationships to improve ecosystem and earth system models. They also will allow, for the first time to our knowledge, representations of root carbon pools that consider biogeographic differences, which are useful for quantifying whole-ecosystem carbon stocks and cycles and for assessing the impact of climate change on forest carbon dynamics.

Ecological importance of intermediate windstorms rivals large, infrequent disturbances in the northern Great Lakes

Exogenous disturbances are critical agents of change in temperate forests capable of damaging trees and influencing forest structure, composition, demography, and ecosystem processes. Forest disturbances of intermediate magnitude and intensity receive relatively sparse attention, particularly at landscape scales, despite influencing most forests at least once per generation. Contextualizing the spatial extent and heterogeneity of such damage is of paramount importance to increasing our understanding of forested ecosystems. We investigated patterns of intermediate wind disturbance across a forested landscape in the northern Great Lakes, USA. A vegetation change tracker (VCT) algorithm was utilized for processing near-biennial Landsat data stacks (1984–2009) spanning forests sustaining damage from four recent windstorms. VCT predominantly maps stand-clearing disturbance and regrowth patterns, which were used to identify forest boundaries, young stands, and disturbance patterns across space and time. To map wind damage severity, we compared satellite-derived normalized difference vegetation index (NDVI) values calculated from pre- and post-storm Landsat imagery. A geographic information system (GIS) was used to derive wind damage predictor variables from VCT, digital terrain, soils/landform, land cover, and storm tracking data. Hierarchical and random forests regressions were applied to rank the relative importance of predictor variables in influencing wind damage. A conservative estimate of aggregate damage from the intermediate windstorms (extrapolated to ∼150,000 ha, ∼25,500 severe) rivaled individual large, infrequent disturbances in the region. Damage patterns were relatively congruent among storms and became more spatially heterogeneous with increasing disturbance intensity. Proximity to forest-nonforest edge, stand age, and soils/landform were consistently important damage predictors. The spatial extent and distribution of the first two damage predictors are extremely sensitive to anthropogenic modifications of forested landscapes, the most important disturbance agent in the northern Great Lakes. This provides circumstantial evidence suggesting anthropogenic activities are augmenting and/or diminishing the ecological effects of the natural wind disturbance regime. Natural disturbances of intermediate size and intensity are significant agents of change in this region, and likely in other regions, deserving more attention from ecologists and biogeographers.

Soil vital signs: A new Soil Quality Index (SQI) for assessing forest soil health

_________________________________________ The Forest Inventory and Analysis (FIA) program measures a number of chemical and physical properties of soils to address specific questions about forest soil quality or health. We developed a new index of forest soil health, the soil quality index (SQI), that integrates 19 measured physical and chemical properties of forest soils into a single number that serves as the soil’s “vital sign” of overall soil quality. Regional and soil depth differences in SQI values due to differences in soil properties were observed. The SQI is a new tool for establishing baselines and detecting forest health trends.

Ohio forests: 2006

This report summarizes annual forest inventories conducted in Ohio from 2001 to 2006 by the Northern Research Stations Forest Inventory and Analysis unit. Ohios forest land covers 7.9 million acres or 30 percent of the States land area, changing little in forest land area since 1991. Of this land, 5.8 million acres (73 percent) are held by family forest owners. The current growing-stock inventory is 12.3 billion cubic feet--2 percent more than in 1991--and averages 1,603 cubic feet per acre. Yellow-poplar continues to lead in volume followed by red and sugar maples. Since 1991, the saw log portion of growing-stock volume has increased by 35 percent to 41 billion board feet. In the latest inventory, net growth exceeded removals for all major species except elm.

The Forest Inventory and Analysis Database Version 4.0: Database Description and Users Manual for Phase 3

Describes the structure of the Forest Inventory and Analysis Database (FIADB) 4.0 for phase 3 indicators. The FIADB structure provides a consistent framework for storing forest health monitoring data across all ownerships for the entire United States. These data are available to the public.

Maine's forests 2008

The second annual inventory of Maines forests was completed in 2008 after more than 3,160 forested plots were measured. Forest land occupies almost 17.7 million acres, which represents 82 percent of the total land area of Maine. The dominant forest-type groups are maple/beech/yellow birch, spruce/fir, white/red/jack pine, and aspen/white birch. Statewide volume equals 25.5 billion ft3, resulting from nearly 590 million ft3 of live-tree volume grown each year. The report also contains additional information on sustainability, biomass, carbon, forest health, land-use change, and timber products. The DVD includes detailed information on forest inventory methods, quality of estimates found, and tables forest statistics.

Indiana's forests 1999-2003 (Part A)

Detailed analyses and interpretation of Indianas inventory data are included in a Part A companion resource bulletin to this compendium of techniques, tables, and definitions.

Michigan's forests 2004

The first annual inventory of Michigans forests, completed in 2004, covers more than 19.3 million acres of forest land. The data in this report are based on visits to 10,355 forested plots from 2000 to 2004. In addition to detailed information on forest attributes, this report includes data on forest health, biomass, land-use change, and timber-product outputs.

Pennsylvania's forest 2004.

Pennsylvanias forest-land base is stable, covering 16.6 million acres or 58 percent of the land area. Sawtimber volume totals 88.9 billion board feet, an average of about 5,000 board feet per acre. Currently, only half of the forest land that should have advance tree seedling and sapling regeneration is adequately stocked with high-canopy species, and only one-third has adequate regeneration for commercially desirable timber species. Several exotic diseases and insects threaten the health of Pennsylvanias forests. Stressors such as drought, acidic deposition, and ground-level ozone pollution are adversely affecting the States forests.

Minnesota's Forests 2008

The second full annual inventory of Minnesotas forests reports 17 million acres of forest land with an average volume of more than 1,000 cubic feet per acre. Forest land is dominated by the aspen forest type, which occupies nearly 30 percent of the total forest land area. Twenty-eight percent of forest land consists of sawtimber, 35 percent poletimber, 35 percent sapling/seedlings, and 2 percent is nonstocked. Additional forest attribute and forest health information is presented along with information on agents of change including changing land use patterns and the introduction of nonnative plants, insects, and disease. Detailed information on forest inventory methods, data quality estimates, and important resource statistics can be found on the Statistics and Quality Assurance DVD included in this report.