Analysis Of Forest Inventory Data Research Articles

Analysis of Forest Inventory Data Shows Disparity in Tree Mortality and Resistance in Texas National Forests

Abstract In 2011, the forestlands of Texas were affected by one of the most severe droughts in the state’s history, killing an estimated 65 million trees in the East Texas region. This study uses USDA Forest Service Forest Inventory and Analysis data and a standardized precipitation-evapotranspiration index to estimate major tree species responses to the 2011 drought in Texas’ four national forests. We used an analysis of variance and a linear mixed-effect model to evaluate factors contributing to tree mortality and growth. We found that tree mortality rates varied greatly during the drought period relative to predrought levels; higher stand age, higher stand density, and higher mean summer temperature contributed to tree mortality volume. Study Implications: Drought is a recurring disturbance agent and is likely to continue to increase in frequency and severity in the future. We provide an understanding of an exceptional drought as a disturbance agent and its impacts on tree mortality and resistance. The effects of the 2011 drought on national forests in Texas have not previously been evaluated. Texas’ national forests represent over 256,975 ha (635,000 ac) in the state’s eastern region and nearly 10% of all public land in Texas. Our results are useful to decision makers in developing strategies and protecting forestlands in the face of potential future droughts.

Countering Omitted Evidence of Variable Historical Forests and Fire Regime in Western USA Dry Forests: The Low-Severity-Fire Model Rejected

The structure and fire regime of pre-industrial (historical) dry forests over ~26 million ha of the western USA is of growing importance because wildfires are increasing and spilling over into communities. Management is guided by current conditions relative to the historical range of variability (HRV). Two models of HRV, with different implications, have been debated since the 1990s in a complex series of papers, replies, and rebuttals. The “low-severity” model is that dry forests were relatively uniform, low in tree density, and dominated by low- to moderate-severity fires; the “mixed-severity” model is that dry forests were heterogeneous, with both low and high tree densities and a mixture of fire severities. Here, we simply rebut evidence in the low-severity model’s latest review, including its 37 critiques of the mixed-severity model. A central finding of high-severity fire recently exceeding its historical rates was not supported by evidence in the review itself. A large body of published evidence supporting the mixed-severity model was omitted. These included numerous direct observations by early scientists, early forest atlases, early newspaper accounts, early oblique and aerial photographs, seven paleo-charcoal reconstructions, ≥18 tree-ring reconstructions, 15 land survey reconstructions, and analysis of forest inventory data. Our rebuttal shows that evidence omitted in the review left a falsification of the scientific record, with significant land management implications. The low-severity model is rejected and mixed-severity model is supported by the corrected body of scientific evidence.

Rapid Assessment of Tree Damage Resulting from a 2020 Windstorm in Iowa, USA

A need to quantify the impact of a particular wind disturbance on forest resources may require rapid yet reliable estimates of damage. We present an approach for combining pre-disturbance forest inventory data with post-disturbance aerial survey data to produce design-based estimates of affected forest area and number and volume of trees damaged or killed. The approach borrows strength from an indirect estimator to adjust estimates from a direct estimator when post-disturbance remeasurement data are unavailable. We demonstrate this approach with an example application from a recent windstorm, known as the 2020 Midwest Derecho, which struck Iowa, USA, and adjacent states on 10–11 August 2020, delivering catastrophic damage to structures, crops, and trees. We estimate that 2.67 million trees and 1.67 million m3 of sound bole volume were damaged or killed on 23 thousand ha of Iowa forest land affected by the 2020 derecho. Damage rates for volume were slightly higher than for number of trees, and damage on live trees due to stem breakage was more prevalent than branch breakage, both likely due to higher damage probability in the dominant canopy of larger trees. The absence of post-storm observations in the damage zone limited direct estimation of storm impacts. Further analysis of forest inventory data will improve understanding of tree damage susceptibility under varying levels of storm severity. We recommend approaches for improving estimates, including increasing spatial or temporal extents of reference data used for indirect estimation, and incorporating ancillary satellite image-based products.

White poplar (Populus alba L.) stands in Ukraine: the current state, growth specificities and prospects of using for forest plantations

Abstract The aim of the study was to assess the current state and evaluate the productivity of white poplar stands by natural zones within Ukraine and to define the prospects for their use for plantation forest cultivation. The objects of the study were white poplar stands in Ukrainian forests grown on the area of more than 7,600 hectares in various natural zones, namely Polissya (forest zone in Ukraine), Forest-Steppe, and Steppe. The study was carried out based on the analysis of forest inventory data (Ukrainian forest fund database) containing given stand characteristics such as origin, age, diameter, height, type of forest site conditions, etc. The characteristics were estimated by grouping the plots by age. The growth specificities (dynamics of the main mensuration characteristics) and the productive capacity of the white poplar stands were analyzed based on the developed tables. It was found that white poplar stands are mainly concentrated in Steppe and Forest-Steppe in Ukraine. The stands are of coppice or artificial origin; they grow in moist fairly fertile, fresh fairly fertile and moist fertile sites. The age distribution of the white poplar stands is severely imbalanced due to a significant predominance of stands aged over 40 years in all natural zones within Ukraine. More productive are the white poplar stands growing within Polissya and Forest-Steppe. The developed growth and productivity tables should be used when planning and prioritizing the relevant forestry interventions in white poplar stands.

Modelling potential density of natural regeneration of European oak species (Quercus robur L., Quercus petraea (Matt.) Liebl.) depending on the distance to the potential seed source: Methodological approach for modelling dispersal from inventory data at forest enterprise level

The use of natural oak regeneration from admixed oaks and neighbouring oak stands provides an interesting alternative to cost-intensive artificial oak regeneration when aiming for forest conversion of pure coniferous stands. In this study analysis of forest inventory data is done on how far and in what density natural regeneration of both Pedunculate and Sessile oak occurs in coniferous stands.In order to investigate as exclusively as possible the effect of distance to the seed source on the regeneration density of both oaks, the regeneration potential was determined by using quantile regression. By applying a .995th quantile, reducing factors on seedling density, e.g. desiccation, browsing, pathogens or limited resource availability, were excluded as much as possible. Thus, the effect of zoochorus vectors on effective dispersal could be quantified.The regeneration potential was determined based on data from the forest inventory of the Saxony state forest enterprise, Germany, including 2357 sample plots. Remote sensing data, including the location of oaks in the overstorey, were used to determine the distance to the nearest potential seed source.The results of the present study demonstrate that the highest regeneration densities are not found in the immediate vicinity of the nearest seed source, but at distances between 60 and 140 m to it, i.e. the maximum of seedling density per area unit is in some distance to the trees trunk. In the present study, dispersal distances of established regeneration up to 1565 m were detected. From a distance of 1570–2300 m on, there was no oak regeneration.The results prove that acorns are taken from the seed source and that, in addition to barochorus dispersal, the zoochorus dispersal is of great importance for the succession of coniferous stands. The position of potential seed sources is therefore an important information for silvicultural planning, in order to estimate potential oak regeneration densities.

Соснові деревостани лісостепу Харківщини: продуктивність і природне поновлення

Наведено матеріали досліджень соснових лісостанів Лісостепу Харківської області. Встановлено основні лісівничо-таксаційні показники деревостанів в основних типах лісорослинних умов регіону дослідження за даними пробних площ. Проаналізовано дані стосовно повноти, запасу, середніх діаметрів і висот відповідно до класів віку. Наведено дані постійних пробних площ у ДП «Скрипаївське НДЛГ» та ділянок інтенсивного моніторингу в ДП «Жовтневе ЛГ» і НПП «Слобожанський». Показано динаміку таксаційних показників на ділянках; особливу увагу звертали на запаси деревостанів. Зроблено опис надґрунтового покриву ділянок за типами лісу, визначено характер розміщення рослин за площею та частку проективного покриття. Окремо встановлено співвідношення покриття на пробних площах трав, лишайників і мохів, показано його залежність від типу лісу. Проаналізовано дані щодо природного поновлення, вказано його густоту, характер розміщення, середні показники висот і діаметрів та їхню залежність від розміщення на ділянці, визначено категорію життєздатності підросту.

Классификация типов лесорастительных условий по индикаторным видам Воробьева-Погребняка: база данных и опыт анализа лесотаксационных данных

Классификация типов лесорастительных условий по индикаторным видам Воробьева-Погребняка: база данных и опыт анализа лесотаксационных данных

Влияние долевого участия сосны и ели на таксационные показатели смешанных древостоев

The influence of composition on the dynamics of inventory indices of the mixed modal forest stands is considered: ridges with the groups of forest types of middle subzone of taiga in the territory of the Leningrad region, for 60 year period. The course of growth of pine and spruce in the mixed stand is due to the composition of the stand, which affects the entire life cycle of its development. Analysis of forest inventory data at the test plots has shown that the median line for the average height and diameter has the distinction of growth from tabular reference data. Differences in the dynamics of growth in valuation metrics over the study period is due to the initial density of pine, then spruce, and the degree of difference in the age of trees. The variability of average heights and diameters on the experimental plots is influenced by the share of particular species in the composition of the stand. The stand composition significantly affects average diameter and height of tiers, composing the mixed coniferous forest that was confirmed by single-factor analysis of variance. The sum of the areas of the cross sections at the pine tier of the virtually at all experienced objects increases up to the age of 100-120 years, and in spruce this dependence is shown only up to the age of 80-85 years. Pine tier depending on the initial density has a greater impact on the composition of the mixed stands than spruce. This can be considered as a fact of environmental compliance of the conditions of the types: ridges with groups of forest types, for successful growth of pine. In mixed stands, untouched by commercial logging, the spruce element, quantitatively not exceeding the pine one, are stunted and produce less stock

重大森林恢复计划下的碳增汇效应——基于石柱县两次森林资源二类清查的分析

重大森林恢复计划下的碳增汇效应——基于石柱县两次森林资源二类清查的分析

Using self-organizing maps in the visualization and analysis of forest inventory

Abstract: A lot of useful data on forest condition can be gathered from the Forest Inventory (FI). Without the help of data analysis tools, human experts cannot manually interpret information in such a large data set. Conventional multivariate statistical analyses provide results that are difficult to interpret and often do not represent the information in a satisfactory way. Our goal is to identify an alternative approach that will enable fast and efficient interpretation and analysis of the FI data. Such interpretation and analysis can be performed automatically with a clustering method, but all clustering methods have some shortcomings. Therefore, our aim was also to provide information in a form suitable for fast and intuitive visualization. Kohonen’s Self Organizing Map (SOM) is an alternative approach to data visualization and analysis of large multidimensional data sets. SOM provides different possibilities and our experiments are presented with component matrices of individual stand parameters and label matrices. In forming data clusters, we experimented with hierarchical and non hierarchical clustering methods. Our experiments showed that SOM provides useful information in a form suitable for data clustering and data visualization. This enables an efficient analysis of large FI data sets at different analysis scales. Clustering results obtained with SOM and two clustering algorithms are in accordance with ground truth. We have also considered the efficiency of SOM component matrices by visual comparison and correlation among structural parameters and by determining contributions of individual stand parameters to clustering input data. SOM application in visualization and analysis of stand structural parameters enables gathering quickly and efficiently holistic information on the current condition of forest stands and forest ecosystem development. Therefore we recommend the application of Kohonen’s SOM for visualization and analysis of FI data.

Site Productivity and Forest Carbon Stocks in the United States: Analysis and Implications for Forest Offset Project Planning

The documented role of United States forests in sequestering carbon, the relatively low cost of forest-based mitigation, and the many co-benefits of increasing forest carbon stocks all contribute to the ongoing trend in the establishment of forest-based carbon offset projects. We present a broad analysis of forest inventory data using site quality indicators to provide guidance to managers planning land acquisition for forest-based greenhouse gas mitigation projects. Specifically, we summarize two condition class indicators of site productivity within the FIA forest inventory database—physclcd and siteclcd—as they relate to current aboveground live tree carbon stocks. Average carbon density is higher on more productive sites, but compared to the overall variability among sites, the differences are relatively small for all but the highest and lowest site classes. Some minor differences in eastern- versus western-forests were apparent in terms of how carbon on the least productive sites differed from most other forest land over time. Overall results suggest that xeric sites in most regions as well as sites that correspond to the lowest, non-productive classifications of forest land should preferentially not be used forestry-based greenhouse gas mitigation projects, but all other forest areas appear to be suitable.

Increased tree carbon storage in response to nitrogen deposition in the US

Spatially extensive evidence for nitrogen-induced stimulation of forest growth has been lacking. Analysis of forest inventory data from the northeastern and north-central US collected during the 1980s and 1990s indicates that nitrogen deposition enhanced above-ground carbon storage by 61 kg per kg of nitrogen deposited. Human activities have greatly accelerated emissions of both carbon dioxide and biologically reactive nitrogen to the atmosphere1,2. As nitrogen availability often limits forest productivity3, it has long been expected that anthropogenic nitrogen deposition could stimulate carbon sequestration in forests4. However, spatially extensive evidence for deposition-induced stimulation of forest growth has been lacking, and quantitative estimates from models and plot-level studies are controversial5,6,7,8,9,10. Here, we use forest inventory data to examine the impact of nitrogen deposition on tree growth, survival and carbon storage across the northeastern and north-central USA during the 1980s and 1990s. We show a range of growth and mortality responses to nitrogen deposition among the region’s 24 most common tree species. Nitrogen deposition (which ranged from 3 to 11 kg ha−1 yr−1) enhanced the growth of 11 species and decreased the growth of 3 species. Nitrogen deposition enhanced growth of all tree species with arbuscular mycorrhizal fungi associations. In the absence of disturbances that reduced carbon stocks by more than 50%, above-ground biomass increment increased by 61 kg of carbon per kg of nitrogen deposited, amounting to a 40% enhancement over pre-industrial conditions. Extrapolating to the globe, we estimate that nitrogen deposition could increase tree carbon storage by 0.31 Pg carbon yr−1.

Forest Type Definitions by Cluster Analysis

Abstract A method is presented to develop forest type definitions by using cluster analysis of forest inventory data collected in southeast Alaska from 1995 through 1998. Species stocking levels were used as variables for cluster development. Pacific Northwest Research Station forest inventory staff could not compute forest type for some forested conditions in southeast Alaska using then existing forest type definitions. Forest type definitions developed by cluster analysis improved computed assignment of forest type. West. J. Appl. For. 16(3):101–105.

Conservation of the forest red-tailed black cockatoo, a hollow-dependent species, in the eucalypt forests of Western Australia

Surveys of the forest red-tailed black cockatoo (FRTBC), Calyptorhynchus banksii naso Gould, conducted in two consecutive breeding seasons, were used to examine the hypothesis that a shortage of suitable nest sites (hollows in standing trees) limits the distribution of the cockatoo. It was found that 36% of its original geographical range is currently unoccupied, presumably because of extensive clearance of woodland for agriculture. FRTBC were broadly distributed nearly all over the State Forest. Analysis of forest inventory data indicates that the supply of large trees (and hence suitable nesting hollows) is not limiting. The current population of FRTBC is estimated to be ca. 15 000 birds.

Sustainable use of the boreal Prince Albert Model Forest in Saskatchewan

Canada recently embarked on a model forest program that is guided by the notion of sustainable development. Ten model forest sites have been established at operational scales (0.1–1.5 million ha) in different ecoregions since 1992. This study presents a framework for advancing both the human welfare and environmental dimensions of sustainable forest use by a localized multi-stake-holdership of First Nations, government and industry in the boreal Prince Albert Model Forest, Saskatchewan. The pressure on the local forest environment has been rising due to timber harvest and tourism. Human welfare has been influenced strongly by colonial legacies such as racial divisions, territorial boundaries, and centralized forest administration. The landbase, productivity and forest value approaches are proposed to advance sustainable forest use; but current data availability favours the land-base approach. Analysis of forest inventory data suggests that management needs to plan for a significant aggregation of harvest areas to sustain ecological and cultural functions which depend on large and continuous patch size. Forest policy-making must address ownership issues, local economic development, and economic philosophies of the stakeholders in order to overcome the colonial legacies and to redefine management responsibilities. The study proposes that the currently dominating government-owned management concepts should evolve into a more localized concept of ownership and management that can be sustainably supported and financed by forest stakeholders, governments, and local communities. Key words: sustainable development, boreal forest, patch size, forest policy-making, stakeholder, First Nation, community