Distribution of carabid beetles among 40-year-old regenerating plantations and 100-year-old naturally regenerated forests in Southwestern China

Effects of reforestation by native tree species on species assemblages of carabid beetles were studied between 40-year-old regenerating plantations and 100-year naturally regenerated forests in Southwestern China. Two old naturally regenerated forest types (ca.100 years old) were chosen: hemlock-spruce forests (Tsuga chinensis and Picea brachytyla) and birch forests (Betula albo-sinensis). Three young regenerating forest types (ca. 40 years old), including spruce plantations (P. brachytyla), larch plantations (Larix kaempferi and Larix mastersian), and natural broad-leaved forests, were established after the logging of the old naturally regenerated forests. Using pitfall traps, we compared the distribution of carabid beetles in the five forest types. Three replicated plots for each forest type were chosen, and each plot was investigated with four trap sites twice each month during the growing season (May to October) in 2004. Our results showed that species richness and abundance were significantly higher in the young regenerating forests than in the old naturally regenerated forests. Analysis of complementarity in carabid species lists across the forest ages and types showed that the old naturally regenerated birch forests had the lowest similarity with the young regenerating larch plantations, and the highest similarity was shown between the two young regenerating plantations. Although PCoA ordination grouped the carabid assemblages according to forest type and forest age, the overall similarity among all forest types was high. Moreover, quantitative character species analysis did not detect significant species associated with forest types and ages. Based on the specificity and fidelity, most carabid species were abundant in all habitats, and only a few species were restricted in one or two forest types. Multiple linear regression between the species richness, abundance and Shannon diversity of carabids and of five environmental variables showed that the cover of canopy and herbaceous layer, and the depth of leaf litter had significant effects in determining richness, abundance and diversity of carabid beetles. Thus, the young regenerating forests at the mature stage could provide an appropriate habitat for most forest species of carabids survived in adjacent old naturally regenerated forests and might replace the role in part of the old-growth forests in sustaining the diversity of carabid assemblages. But some species are still restricted in old naturally regenerated forests, so in order to protect the diversity of carabid assemblages, it is necessary to sustain the intact old naturally regenerated forests when reforesting with some native tree species following natural succession.     

Differences in abundance,species richness,and body size of ground beetles (Coleoptera: Carabidae) between beech (Fagus sylvatica L.) forests on Podzol and Cambisol

Ten forest sites with a tree layer of almost pure beech in southern-central Scania, south Sweden, were studied. They were all located in the interior of large forest stands. Five of the stands were developed on mor Podzols with scanty or almost no ground layer vegetation. The other five sites were located on mull Cambisols with a rich ground layer of many vascular plant species and a shrub layer of varying density. In total, 42 carabid beetle species and 9260 individuals were captured with pitfall traps (15 per site, diameter 87 mm) during 12 weeks in April, July and September 2007. Composition of the carabid fauna differed considerably between the two types of sites. In the Cambisol sites 39 carabid species were found, compared to only 21 species in the Cambisol sites. Mean carabid species richness per site differed significantly between Cambisol and Podzol sites (n = 20.4 and 13.2, respectively). The difference was wholly due to a lower number of small carabid species (mean body length <12 mm) in the Podzol sites. Of four variables (pH-KCl, Clay, Organic matter, and Sum of plant cover percentages below tree canopy) the sum of plant cover variable usually accounted for more (>50%) of the carabid beetle variability compared to the three other variables. Carabus glabratus and Pterostichus oblongopunctatus were almost exclusively found on Podzol. Carabus coriaceus, Pterostichus melanarius and in particular Carabus nemoralis were more abundant on Cambisol, whereas Carabus hortensis and Pterostichus niger were almost ubiquitous and attained the highest total numbers. There was no significant difference between Podzol and Cambisol sites in the total number of carabid individuals captured. C. coriaceus, C. hortensis, and Carabus violaceus, species that were abundant enough in all sites for a comparison, had significantly larger mean body sizes in the Podzol than in the Cambisol sites, a finding valid for both sexes. There were more males than females of C. coriaceus, C. violaceus, and C. nemoralis in the catches, whereas sex distribution of C. hortensis was equal. Possible explanations for the findings are differences in microclimate and food web characteristics related to differences between Podzols and Cambisols in understorey vegetation and soil or litter properties.     

Determining the vulnerability of Mexican pine forests to bark beetles of the genus Dendroctonus Erichson (Coleoptera: Curculionidae: Scolytinae)

Bark beetles of the genus Dendroctonus are natural inhabitants of forests; under particular conditions some species of this genus can cause large-scale tree mortality. However, only in recent decades has priority been given to the comprehensive study of these insects in México. México possesses high ecological diversity in Dendroctonus–Pinus associations. The geographic coexistence of 12 Dendroctonus species suggests greater vulnerability or threat of tree mortality relative to other areas. We use a biogeographic strategy to identify and rank the areas most vulnerable to tree mortality caused by bark beetles in México. We aim to define the areas that might experience high impact by these insects and also to provide a geographic database useful to forest resource management and conservation policies in México. Using collection records of bark beetles and pines, we develop a quantitative estimate of the threat of beetle infestation of forest areas based on factors including pine and beetle species density, host preference and level of mortality caused by beetle species. A quantitative estimate of forest area vulnerability, the Bark Beetle Threat Index (BBTI) was calculated. Despite the vast area of geographic coincidence of Pinus and Dendroctonus in México, the regions of highest bark beetle pressure are restricted to small zones within some mountain systems. The region that has been most affected by this insect group during the past hundred years is the Transverse Volcanic Belt, followed by the Sierra Madre Occidental and Sierra Madre del Sur. Pine diversity is the major determining factor of BBTI at the regional level, while disturbances from extensive logging and ecosystem change are the key factors behind high BBTIs at the local level.     

Spatial distribution pattern of attack of the oak borer,Platypus quercivorus (Murayama) (Coleoptera: Platypodidae), and scolytid ambrosia beetles (Coleoptera: Scolytidae) on fresh logs

The spatial distribution patterns of the attack on fresh logs ofPasania edulis was studied for the oak borer,Platypus quercivorus (Murayama), and two species of Scolytid ambrosia beetles,Xylosandrus crassiusculus (Motschulsky) andXyleborus attenuatus Blanford, in 1994 and 1995. On the logs where onlyP. quercivorus attacked, the entry holes were distributed uniformly when attack intensity was low. However, the distribution pattern became more aggregated with the increase in attack intensity. On logs where bothP. quercivorus and the two Scolytid species attacked, there was a negative association between the spatial distribution of the entry holes ofP. quercivorus and that of scolytids. Simultaneous attack of two scolytids also increased the degree of aggregation of the entry holes ofP. quercivorus. The entry holes of scolytids were distributed in groups irrespective of the attack intensity of scolytids andP. quercivorus. These results suggest an asymmetrical interspecific relationship betweenP. quercivorus and scolytids. Concentration of the entry holes ofP. quercivorus in a small area may cause a considerable decline in the reproductive success in the galleries constructed there.     

Studies on the abundance, biology and harmfulness of leaf beetles (Coleoptera: Chrysomelidae) in natural bush vegetation in Isparta, Turkey

Leaf beetle occurrence and abundance on certain shrubs and bushes were surveyed during 2002–2003 in several natural habitats of Isparta. The 34 leaf-beetle species collected are listed and classified according to their relative percentage of the total caught and to their associated host plants. In all habitats sampled, leaf beetles showed a preference for plants from the genera Quercus and Crataegus. Some abundant species causing serious damage to their food plants are discussed.     

Comparison of beta,Johnson’s SB,Weibull and truncated Weibull functions for modeling the diameter distribution of forest stands in Catalonia (north-east of Spain)

The purpose of this study was to compare the beta, Johnson SB, Weibull and truncated Weibull functions in describing the diameter distributions of forest stands in Catalonia. The data consisted of permanent sample plots from the Spanish National Forest Inventory in Catalonia. The empirical data represent left-truncated distributions, as the smallest diameter measured in the field was 7.5 cm. A total of 1,242 plots were used to fit the functions and analyze their performance. The distribution functions were fitted to the diameter distributions of the number of stems (DD_N) and stand basal area (DD_G). The performance of the candidate functions was compared by means of their bias and RMSE for different diameter sums measuring the difference between the empirical and fitted distributions. The leftmost part (from 0 to 7.5 cm) of the non-truncated functions was ignored in this analysis. Sensitivity analyses were conducted to check whether the results depended on the number of trees measured in the stand, or the main species of the stand. The truncated Weibull function for the diameter distribution of stand basal area appeared to be in all cases the most accurate and consistent function. Generally, functions describing the distribution of stand basal area performed better than functions that described the distribution of the number of trees. Of the basal area distributions, beta and Johnson’s SB were the second best and nearly equally good with each other. The order of precision of the tested functions was: truncated Weibull for DD_G, truncated Weibull for DD_N, Johnson’s SB for DD_G, beta for DD_G, beta for DD_N and Weibull for DD_G, Weibull for DD_N, and Johnson’s SB for DD_N.     

Distribution and composition of carabid beetle (Coleoptera, Carabidae) communities across the plantation forest cycle—Implications for management

If national afforestation targets are met, the proportion of area under plantation forest cover in Ireland will almost double by the year 2030 to 17%, and will consist of mostly non-native trees. There is an urgent and vital need to assess and to maximise the biodiversity potential of these forests. This study compares carabid beetle (Coleoptera, Carabidae) composition and assemblage patterns across different stages of the forest cycle, in addition to intensive grassland habitats, the habitat the plantation forest will most likely be replacing. The clearfell habitat had the highest median species richness, while the grassland habitat had the highest species diversity, but lowest species dominance. Ordination analysis revealed that the species assemblages of all stages of the forest cycle could be clearly separated from the grassland habitat, while differences were also observed between forest stages. Canonical correspondence analysis revealed that the most significant factors influencing carabid community composition were percent cover of ground vegetation and mosses, and also percent soil moisture. Differences in species with varying physical traits and microhabitat preferences were also observed between habitats, with larger, brachypterous species positively associated with increasing canopy cover and smaller macropterous species displaying the opposite pattern. The presence and abundance of forest-associated species increased with increasing plantation age, with a corresponding decrease in open habitat-associated and generalist species. The results of this study suggest that at the landscape scale, a variety of different aged forest stands would maximise the biodiversity potential of the planned afforestation.     

Nutrient distribution and accumulation patterns of natural secondary forests in the Loess Plateau of Shanxi Province, northern China

We studied the biomass and its allocation in natural secondary forests, as well as the amounts, accumulation and distribution of nutrient elements (N, P, K, Ca and Mg) in sample plots established in the Loess Plateau in Shanxi Province, northern China. The results show that biomass in natural secondary forests amounted to 36.09 t/hm², of which the tree layer accounted for 46%, the shrub layer for 29%, the herb layer for 13% and the litter layer for 12%. The total storage of the five nutrient elements is 1089.82 kg/hm². Nutrient storage in the tree layer is the largest, at 41%. The sequence of storage of the elements varied among different layers and is given as follows: shrub layer 31.27%, herb layer 12.55% and litter layer 15.36%. The accumulation of nutrient elements in the tree layer, ordered from high to low, is: branches > roots > stems >bark > leaves. The total storage of the five nutrient elements in the soil is 634.97 t/hm², where the accumulation of the nutrients accounts for 95.32% (N), 99.64% (P), 99.91% (K), 99.84% (Ca) and 99.95% (Mg) of the total amounts. The accumulation coefficients of different organs in the tree layer are, from high to low: leaves > branches > roots > bark > stems. The accumulation coefficients in the different layers are listed as follows: shrub layer > tree layer > herb layer and for the elements as: N > P > Ca > K > Mg. __________ Translated from Journal of Beijing Forestry University, 2008, 30(3): 57–62 [译自: 北京林业大学学报]     

Growth and structure development of semi-natural larch-spruce-fir (Larix olgensis–Picea jezoensis–Abies nephrolepis) forests in northeast China: 12-year results after thinning

Analyzing and understanding the structure and growth dynamics of semi-natural plantations is useful for their management. Since 1987, 16 plots with 4 treatments (CT: control; LT: light thinning; MT: medium thinning; and HT: heavy thinning) by 0, 20, 30 and 40% of basal area removal, respectively, and four replications were established in semi-natural larch-spruce-fir forests in northeast China. The structure and growth dynamics of semi-natural larch-spruce-fir stands and the effects of thinning on the growth, structure and diversity were examined. A mixed model repeated measures analysis of variance (RMANOVA) was used to test the effects of treatment and time.

Results showed that differences in periodic annual increment (PAI) of stand basal area and volume and the individual diameter and volume among treatments changed over time in a complex statistical interaction. Thinning, however, had a significant effect on growth at tree and stand levels 12 years after thinning while the PAI of the diameter, basal area and volume was positively correlated with thinning intensity. No significant differences were found in the total stand yield among treatments. Composition of tree species group (larch, other conifers and deciduous trees) during monitoring years did not change significantly. Moreover, no significant differences were observed in tree species and size diversity among treatments in the years following thinning. Both thinning and control plots had similar understory plant diversity after the 12 year period. Univariate point pattern analysis revealed that clumped and random distributions were dominant for tree species groups in this study. The current species composition and regeneration dynamics within these semi-natural plantations suggested a development towards mixed coniferous and broad-leaved forests. Management implications for the transformation from larch plantations towards mixed broad-leaved Korean forests with a more diverse structure, the climax vegetation in this region, were discussed.     

油茶幼林茶角胸叶甲成虫空间分布型及其环境解释

The spatial distribution patterns of Basilepta melanopus adults in Camellia oleifera ( tea oil camellia) young forests of three different ages were studied using aggregation index examination and regre...     

云南省松墨天牛生物学特性和地理分布研究

松墨天牛是云南省近年来危害云南松最为严重的蛀干害虫之一。该虫在滇中地区1a发生1代．以3、4龄幼虫在寄主枝干的木质部内越冬。成虫3月下旬羽化，4月上、中旬为羽化盛期。由于该虫在云南省的寄主分布广，繁殖条件适宜，加之扩散途径多、种群密度大等因素，致使分布范围迅速扩散，造成极大的直接和潜在危害。文中针对松墨天牛在云南省的危害特点提出防治措施。     

宁夏黄土丘陵区不同生态恢复生境中步甲对微生境的选择

[目的]研究不同生境中步甲科昆虫对微生境的选择,探讨生态恢复对维持步甲物种多样性的影响,以期揭示生态恢复进程,并为生物多样性保护提供理论依据。[方法]2012和2013年6—8月,利用陷阱法比较分析了宁夏黄土丘陵区灌草混交林地、乔灌混交林地、生态薪炭林地、生态经济林地、天然封育草地和水平农田6种生境内的步甲物种多样性,应用二分类Logistic回归模型,构建步甲科昆虫的生境选择模型,研究各生境中影响物种生境选择的关键环境因子。[结果]共捕获步甲3236号,隶属于9属16种,其中,直角通缘步甲、麻步甲和赤胸长步甲为优势种,数量分别占40.64%,24.13%和20.02%;步甲个体数量和Shannon-Wiener多样性指数在6种生境中存在显著差异(df=5,P=0.011;df=5,P=0.021),物种丰富度虽在灌草混交生境中高于其他生境,但未达显著差异(df=5,P=0.062);Chao-1丰富度估计曲线显示,灌草混交和生态薪炭林地生境中步甲丰富度达到渐进水平,诱集到几乎所有的步甲物种;天然封育草地和水平农田生境中物种丰富度近似达到渐进水平,诱集到大部分步甲物种;乔灌混交和生态经济林地生境的步甲物种丰富度没达到渐进水平,物种丰富度的估计存在较大变异;3种优势物种在不同生境中的发生概率显著不同;Logistic回归分析表明,草本生物量和土壤含水量是影响直角通缘步甲生境选择的关键环境因子;林冠层盖度、灌木层盖度、草本生物量和土壤含水量是影响麻步甲生境选择的关键环境因子;灌木层盖度、草本盖度、枯落物厚度、草本生物量和土壤含水量是赤胸长步甲生境选择的关键环境因子。[结论]宁南黄土丘陵区步甲对微生境的选择表现出明显的差异性,可作为生态恢复评价的重要指示生物,研究其对生境类型的偏好性进一步加强指导生态恢复和生境保护,对生物多样性保护及生态恢复建设具有实际的推广意义。     

庞泉沟自然保护区隐翅虫亚科级多样性

采用巴氏罐诱法,对庞泉沟国家级自然保护区的不同功能区——核心区(绿色长廊)、缓冲区(八道沟)、远离农田的实验区(神尾沟)及靠近农田的实验区(八水沟)林地地表隐翅虫亚科级甲虫物种多样性进行调查研究,旨在探明该保护区有代表性林地隐翅虫的物种组成及受不同程度人为干扰下的隐翅虫多样性格局。结果表明:1)共捕获隐翅虫标本1862号,分属于9亚科。其中,前角隐翅虫亚科为优势类群,与四眼隐翅虫亚科、异形隐翅虫亚科、隐翅虫亚科和尖腹隐翅虫亚科一起构成研究样地的常见类群。2)不同功能区生境中隐翅虫物种组成和数量分布各不相同,个体数量核心区最多,其他α多样性各项指标均为缓冲区最高,βw为靠近农田实验区最高。3)群落相似性分析表明核心区与其他3个生境差异性较大,缓冲区与其他3个生境有一定程度上的相似。适度干扰可提高物种多样性,降低人为过度干扰有利于增加隐翅虫生物多样性。     

Age structure and regeneration of subalpine fir (Abies fargesii) forests across an altitudinal range in the Qinling Mountains,China

Age structure and regeneration dynamics of subalpine fir (Abies fargesii) forest were studied across the altitudinal range in both the north and south aspects of the Qinling Mountains, China. Ages of individual fir trees were determined based on the number of rings counted from cores and the number of years to reach coring height estimated using age–height regression. Fir age structure and regeneration dynamics were similar in both the north and south aspects. A unimodal population age structure was found at the low- and mid-elevations in both aspects, indicating that environmental factors might play an important role in shaping A. fargesii age structure and regeneration at those sites. There was a recruitment pulse during the time period 1830–1890 at each altitudinal site, but no stem recruitment occurred at the low- and mid-elevations in the last century, which might be attributed to the intensive cover of understory bamboo. Fir trees were, however, persistently recruited at the upper limits during the last 150 years, and the fir tree density at the upper limits was significantly higher than that at the lower limits in both aspects. The fir population at the upper limits showed a significant increase in recruitment and stem density relative to the fir population at the low- and mid-elevations in the last century. We propose that the differences in recruitment might promote variations in stand structure and regeneration dynamics of the subalpine fir forests along the altitudinal gradient in the Qinling Mountains, China.     

Patterns of biomass,carbon,and nitrogen storage distribution dynamics after the invasion of pine forests by Bursaphelenchus xylophilus (Nematoda: Aphelenchoididae) in the three Gorges Reservoir Region

Masson pine stands infected by Pine wilt disease(PWD) in the Three Gorges Reservoir Region of central China were surveyed to quantify the immediate responses and subsequent trajectories of biomass,carbon(C),and nitrogen(N) in stand-level major ecosystem compartments.The biomasses of above-and belowground tree components,as well as of the understory,forest floor,and mineral soil(0–40 cm),were determined within each stand.C and N storage were also estimated for each ecosystem compartment.Overstory biomass decreased steadily with the extent of PWD infection.Understory biomass ranged from1.97 to 4.16 Mg ha~(-1),and the observed value for forest floor biomass was 12.89–22.59 Mg ha~(-1).The highest mean C and N concentrations were found in the stem bark and needles of Masson pine,respectively,while the lowest were found in the semi-to fully decomposed layer of the forest floor and stem wood of Masson pine,respectively.The C and N storage of aboveground trees,tree roots,and the aboveground ecosystem decreased with the extent ofPWD infection.However,the C and N contents of the understory,forest floor,and total mineral soil initially declined after PWD infection before recovering over the following several years.Those result concluded that the biomass,C,and N storage of different forest ecosystem compartments have experienced certain variations following the PWD epidemic.This is vital to understand the shifts in stand-level C and N allocation in PWD-damaged forest stands,as well as for predicting the responses of regional and global C and N cycling.     

The impact of fire and density-dependent mortality on the spatial patterns of a pine forest in the Hulun Buir sandland,Inner Mongolia,China

Wildland fire, especially surface fire, is one of the major disturbances in forest ecosystems such as the Mongolian pine forest of the Hulun Buir sandland. However, little is known about the impact of fire on the spatial patterns at the stand level and its consequences for successional dynamics. To fill this gap we mapped three plots of Mongolian pine forest comprising sites of the same age that were affected by fire in 2006 and 1994, and a site without fire. We explored the stand structure using diameter at breast height (DBH) distributions and basal area, and used point pattern analysis to quantify the observed spatial patterns. Null models included homogeneous Poisson and Thomas cluster processes for univariate analyses, toroidal shift to test for independence, and random labelling for analyzing mortality. Large stems showed at all three stands a tendency to regularity, whereas small stems were mostly clustered. However, small stems did not become more regular at plots with earlier fire, and only the “overstocked” 2006 pre-fire stand showed negative association between large and small trees. Mortality was non-random, showing clustering of dead (or surviving) trees and clear density dependence where stems with more neighbors had a higher risk to die. Fire killed mostly smaller trees and after prolonged fire-free periods the stand approached the pre-fire patterns structurally and spatially. Our study showed that surface fire causes strong thinning in later succession stages and pushes the forest into maturity. It may also enhance resistance of our forest to more severe fire under the relatively harsh environmental conditions. A novel test statistic for random labeling allowed directly testing for density-dependent mortality and could be widely applied in point pattern analysis.     

东北东部天然次生林的景观类型空间连接与分布规律--以黑龙江省帽儿山林场为例

帽儿山地区是东北东部山区较典型的天然次生林区。本文利用ARC／INFO软件，对帽儿山林场景观类型最小距离指数和景观连接度指数进行分析，进而对帽儿山林场各景观类型的空间分布规律进行了探讨。结果表明：有林地与无林地的景观连接度有明显差异，无林地的景观连接度普遍大于有林地；天然林的景观连接度都接近于O，景观破碎化程度较高。人工林的最小距离指数低于天然林和非林地；人工林中，人工针叶混交林的距离指数最小，格局接近于团聚分布；天然林的景观格局近于随机分布；非林地中，采伐迹地的距离指数最小，接近于团聚分布。图2参15。     

THE STATUS AND CONSERVATION OF WILDFOWL(ANATIDAE) IN HEILONGJIANG PROVINCE, CHINA

INTRODUCTPNHeilongiiangProvinceislocatedinnorth-eaStChina(l2l"l9,-l3"55'Eand43"35,-53"o5'N).Itstotalareaisabout4.6xlo5kInzandabout4.8%ofChinatemtory.AndthelargestmarshIandinChina--TheSan-jiangPlain,withanareaofoverl.oxlO'k,112islocatedhere.ThismarshlandprovidesanexceIlenthabitatsforwaterfOwsIllLittledaawasavailableonbirdsintheregronbefOrel96os.Thegovernn1entofHeilonaiiangProvinceorganizedtwosurveysofwildlifeinthelQ7Osandl983resPechvely.nsTEWroareruODSThewholesurveyonnumberandd…     

Landscape pattern and fragmentation of natural secondary forests in the eastern mountainous region, northeast China: A case study of Mao'ershan forests in Heilongjiang Province

Mao'ershan region is a representative natural secondary forested region in the eastern mountainous region, northeast of China. Under the support of ARC/INFO and GIS technology, the landscape shape and fragment indices of Mao'ershan experimental plantation were studied by combining the forest type map (1∶10000), which was drawn from the aerial photographs (1999), field investigation (1999) and soil utilized map (1∶10000). The results showed that the shape index and shape fragment index of natural landscape were higher than those of artificial landscapes and landscape patch fragment index depended on the number of patches. The natural forest had complex shape, suffering little jamming, and its shape index was higher than that of artificial forest. The manual controlled landscape (e.g. nursery, cropland and cutting blank) had regular shape, and its shape index was smaller. The fragment index of patches in natural forest was higher than that of artificial forest. The soft broad-leaved had the highest fragment index of patch amount. Foundation item: This paper was supported by National Key Technologies P&D Program of China during the 10^th Five-Year Plan Period (2002BA515B040). Biography: LI Shu-juan (1977-), female, Lecturer in Ocean University of China, Qingdao 266003, P. R. China. Responsible editor: Zhu Hong     

Historical fire and vegetation dynamics in dry forests of the interior Pacific Northwest,USA, and relationships to Northern Spotted Owl (Strix occidentalis caurina) habitat conservation

Regional conservation planning frequently relies on general assumptions about historical disturbance regimes to inform decisions about landscape restoration, reserve allocations, and landscape management. Spatially explicit simulations of landscape dynamics provide quantitative estimates of landscape structure and allow for the testing of alternative scenarios. We used a landscape fire succession model to estimate the historical range of variability of vegetation and fire in a dry forest landscape (size ca. 7900 km²) where the present-day risk of high severity fire threatens the persistence of older closed canopy forest which may serve as Northern Spotted Owl (Strix occidentalis caurina) habitat. Our results indicated that historically, older forest may have comprised the largest percentage of the landscape (∼35%), followed by early successional forest (∼25%), with about 9% of the landscape in a closed canopy older forest condition. The amount and condition of older forest varied by potential vegetation type and land use allocation type. Vegetation successional stages had fine-grained spatial heterogeneity in patch characteristics, with older forest tending to have the largest patch sizes among the successional stages. Increasing fire severities posed a greater risk to Northern Spotted Owl habitat than increasing fire sizes or frequencies under historical fire regimes. Improved understanding of historical landscape-specific fire and vegetation conditions and their variability can assist forest managers to promote landscape resilience and increases of older forest, in dry forests with restricted amounts of habitat for sensitive species.