Interpreting multiscale domains of tree cover disturbance patterns in North America

Spatial patterns at multiple observation scales provide a framework to improve understanding of pattern-related phenomena. However, the metrics that are most sensitive to local patterns are least likely to exhibit consistent scaling relations with increasing extent (observation scale). A conceptual framework based on multiscale domains (i.e., geographic locations exhibiting similar scaling relations) allows the use of sensitive pattern metrics, but more work is needed to understand the actual patterns represented by multiscale domains. The objective of this study was to improve the interpretation of scale-dependent patterns represented by multiscale domains. Using maps of tree cover disturbance covering North American forest biomes from 2000 to 2012, each 0.09-ha location was described by the proportion and contagion of disturbance in its neighborhood, for 10 neighborhood extents from 0.81 ha to 180 km2. A k-means analysis identified 13 disturbance profiles based on the similarity of disturbance proportion and contagion across neighborhood extent. A wall to wall map of multiscale domains was produced by assigning each location (disturbed and undisturbed) to its nearest disturbance profile in multiscale pattern space. The multiscale domains were interpreted as representing two aspects of local patterns – the proximity of a location to disturbance, and the interior-exterior relationship of a location relative to nearby disturbed areas.Ye

TREE-RING BULLETIN, Vol. 50,1990 ANALYSIS OF BIWEIGHT SITE CHRONOLOGIES: RELATIVE WEIGHTS OF INDIVIDUAL TREES OVER TIME

The relative weights on individual trees in a biweight site chronology can indicate the consistency of tree growth responses to macroclimate and can be the basis for stratifying trees in climate-growth analyses. This was explored with 45 years of ring-width indices for 200 trees from five even-aged jack pine (Pinus hanksiana Lamb.) stands. Average individual-tree relative weights were similar, but most trees had at least one transient occurrence of low relative weight. The standard deviations of individualtree relative weights suggested that some trees had more vaable growth responses than others. The trees were classified by the average and standard deviation of their relative weights, and biweight site chronologies were then calculated for these subgroups. Chronologies derived from trees with low average weights, and from trees with high standard deviation of weights, sometimes appeared to be different from chronologies derived from the remaining trees. Die relativenGewichteeinzelner Baume ineinerdurch 'robuste Mittelung'entstandenen Chronologie ('biweight site chronology') konnen ein Hinweis auf Zusammenhange zwischen den Wachstumsreaktionen von Baumen und dem Makroklima sein unddann als Grundlage zur Stratifizierung der Baume in einer Klima-Wachstums-Analyse dienen. Dies wurde anhand von 45jiihringen Jahrringlndexzeitreihe

Habitat Degradation using Land-Cover Data

The effects of landscape context on habitat quality are receiving increased attention in conservation biology. The objective of this research is to demonstrate a landscape-level approach to mapping and evaluating the anthropogenic risks of grassland and forest habitat degradation by examining habitat context as defined by intensive anthropogenic land uses at multiple spatial scales. A landscape mosaic model classifies a given location according to the amounts of intensive agriculture and intensive development in its surrounding landscape, providing measures of anthropogenic risks attributable to habitat isolation and edge effects at that location. The model is implemented using a land-cover map (0.09 ha/pixel) of the conterminous United States and six landscape sizes (4.4, 15.2, 65.6, 591, 5300, and 47800 ha) to evaluate the spatial scales of anthropogenic risk. Statistics for grassland and forest habitat are extracted by geographic overlays of the maps of land-cover and landscape mosaics. Depending on landscape size, 81 to 94 percent of all grassland and forest habitat occurs in landscapes that are dominated by natural land-cover including habitat itself. Within those natural-dominated landscapes, 50 percent of grassland and 59 percent of forest is within 590 m of intensive agriculture and/or intensive developed land which is typically a minor component of total landscape area. The conclusion is that anthropogenic risk attributable to habitat patch isolation affects a small proportion of the total grassland or forest habitat area, while the majority of habita

A global evaluation of forest interior area dynamics using tree cover data from 2000 to 2012

Context Published maps of global tree cover derived from Landsat data have indicated substantial changes in forest area from 2000 to 2012. The changes can be arranged in different patterns, with different conse- quences for forest fragmentation. Thus, the changes in forest area do not necessarily equate to changes in forest sustainability. Objective The objective is to assess global and regional changes in forest fragmentation in relation to the change of forest area from 2000 to 2012. Methods Using published global tree cover data, forest and forest interior areas were mapped in 2000 and 2012. The locations of forest interior change were compared to the locations of overall forest change to identify the direct (pixel level) and indirect (landscape level) components of forest interior change. The changes of forest interior area were compared to the changes of total forest area in each of 768 ecological regions. Results A 1.71 million km2 (3.2 %) net loss of global forest area translated to a net loss of 3.76 million km2 (9.9 %) of forest interior area. The difference in loss rates was consistent in most of the 768 ecological regions. The indirect component accounted for 2.44 million km2 of the net forest interior change, com- pared to 1.32 million km2 that was attributable to the direct component. Conclusion Forest area loss alone from 2000 to 2012 underestimates ecological risks from forest fragmen- tation. In addition to the direct loss of forest, there was a widespread shift of the remaining global forest to a more fragmented condition.JRC.H.3-Forest Resources and Climat

Early genetic selection in Douglas-fir : interactions with shade, drought, and stand density

This thesis is concerned with developing techniques for identifying "superior" Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco) parent trees based on seedling progeny evaluation. The growth responses of up to 14 open-pollinated families to shade, drought, and stand density were assessed in four experiments. A technique was developed to compare family height growth responses to increasing stand density while accounting for genetic variation in growth rates. Family rankings based on seedling evaluation criteria were compared with 15-year growth records for an earlier cohort from the same parent trees. The significant findings of this study were: (1) fifteen-year field height rankings were related to differences in budset date, height growth rate, and branchiness among seedlings grown with or without shade or drought stress; (2) seedling-field correlations were inversely related to seedling-seed weight correlations; (3) seedling-field correlations improved with age in the field; (L) family correlations between spaced-plant growth and closed-stand growth were low for measures of seedling size but high for measures of seedling shape, and; (5) there was genetic variation in height growth responses to increasing stand density in single-family seedling plots

FAO – State of the world’s forests: forest fragmentation

This document summarizes the design process, definitions, and algorithmic implementation conducted by the Joint Research Centre to support the development and implementation of FAO’s global forest analysis for the thematic topics Accounting and Fragmentation. The analysis scheme and data products were designed to support the indicator Forest Fragmentation in the State of the World's Forests (SOFO) report 2020. The spatial forest coverage is assessed from the Copernicus Global Land Cover 2015 dataset (accessed in July 2019) and 21 Global Ecological Zones (GEZ). All data was re-projected to equal area to allow for comparable area estimates across the Globe. Spatially explicit maps and statistical summaries are derived at global level and for each of the 21 GEZ.JRC.D.1-Bio-econom

An approach for pan-European monitoring of forest fragmentation

This document describes the design process, definitions, and algorithmic implementation for the pan-European Assessment of Forest Fragmentation. This study is a preceding presentation of the indicator 4.7 in the State of Europe’s Forests 2020 report, published by FOREST EUROPE. The spatial forest coverage is assessed from the Copernicus CORINE Land Cover dataset (CLC, version 20, downloaded in July 2019) for the years 1990, 2000, 2006, 2012, 2018. Spatially explicit maps and statistical summaries are derived at three reporting levels: CLC (entire CLC coverage), EU28 and at country level. The status product consists of maps and summary statistics for each year and assessment level. The change product highlights areas where non-forest and forest fragmentation classes changed over time. The change product is provided for the time frame 2000 to 2018, which is the longest time span with comparable data coverage.JRC.D.1-Bio-econom

A key to the literature on forest growth and yield in the Pacific Northwest, 1910-1981

Tables are presented that summarize 108 published articles on forest growth and yield in the Pacific Northwest. Each table describes the form of the information presented, the species to which the information is applicable, the data sources used to develop the information, the data needed to predict growth and yield, and the form of the predicted data

Analysis of Biweight Site Chronologies: Relative Weights of Individual Trees over Time

The relative weights on individual trees in a biweight site chronology can indicate the consistency of tree growth responses to macroclimate and can be the basis for stratifying trees in climate-growth analyses. This was explored with 45 years of ring-width indices for 200 trees from five even-aged jack pine (Pints banksiana Lamb.) stands. Average individual-tree relative weights were similar, but most trees had at least one transient occurrence of low relative weight. The standard deviations of individual-tree relative weights suggested that some trees had mom variable growth responses than others. The trees were classified by the average and standard deviation of their relative weights, and biweight site chronologies were then calculated for these subgroups. Chronologies derived from trees with low average weights, and from trees with high standard deviation of weights, sometimes appeared to be different from chronologies derived from the remaining trees.This item is part of the Tree-Ring Research (formerly Tree-Ring Bulletin) archive. It was digitized from a physical copy provided by the Laboratory of Tree-Ring research at The University of Arizona. For more information about this peer-reviewed scholarly journal, please email the Editor of Tree-Ring Research at [email protected]

Evenness Indices Measure the Signal Strength of Biweight Site Chronologies

The signal strength of a biweight site chronology is properly viewed as an outcome of analysis rather than as a property of the forest-climate system. It can be estimated by the evenness of the empirical weights that are assigned to individual trees. The approach is demonstrated for a 45-year biweight chronology obtained from 40 jack pine (Pinus banksiana Lamb.) trees. The annual evenness of the empirical weights is calculated by indices derived from the Shannon and Simpson diversity indices, and the variances are found by the jackknife procedure. The annual estimates are then averaged to find an overall estimate of biweight signal strength for the 45-year period. These techniques are most useful for determining sample sizes for the biweight procedure, and for comparing different methods of detrending and standardizing data sets prior to applying the biweight mean-value function.This item is part of the Tree-Ring Research (formerly Tree-Ring Bulletin) archive. It was digitized from a physical copy provided by the Laboratory of Tree-Ring research at The University of Arizona. For more information about this peer-reviewed scholarly journal, please email the Editor of Tree-Ring Research at [email protected]