Gap-phase Regeneration Research Articles

Native tree species prosper while exotics falter during gap-phase regeneration, but only where deer densities are near historical levels

Native tree species prosper while exotics falter during gap-phase regeneration, but only where deer densities are near historical levels

A forest gap is not forever: Towards an objective standard to determine when a gap is considered closed in temperate forests

Forest gaps create environmental heterogeneity and drive forest dynamics through gap-phase regeneration. However, it is unclear when a forest gap can be considered closed, limiting a global synthesis of forest succession that integrates gap patterns and dynamics. We created twelve forest gaps (six large gaps, RD/H [ratio of gap diameter to gap border tree height] = 1.3; six small gaps, RD/H = 0.6) and monitored tree regeneration for seventeen years to establish an objective gap-closure standard for regeneration filling in a temperate secondary forest. Our results indicated that a forest gap could be considered closed or entering a gap-closure phase when the dominant gap regeneration layer (i.e., the top 10% gap-fillers) (1) reached the crown base height (8.9 m on average) of canopy trees and (2) entered a period of stability in density, richness, and evenness. Linear mixed-effects models found that these two conditions met each other in the same period (14.5 years) in the large gaps, with a mean density, richness, and evenness of 0.1 (stem m−2), 4.9 (species gap−1), and 0.9, respectively. However, if no repeated gap disturbance occurred, small gaps were closed by lateral extension rather than by height growth. Light-demanding species (e.g., Juglans mandshurica) mainly contributed to the closure of large gaps and played negligible roles in the small gaps, but intermediate or shade-tolerant species (e.g., Acer mono) in the small gaps had potential for successful gap filling following repeated gap disturbance. Our gap-closure standard links gap structure to species composition and provides a reference for large-scale research on gap patterns and dynamics, which helps to understand the ecological process during forest succession. The standard also provides a relatively clear boundary between forest gaps and closed forest stands, which is a premise to develop appropriate forest management and shorten the restoration period of degraded secondary forests.

Canopy Gap phase regeneration: A study in moist temperate forests of Central Himalayas, India

Broad leaved forests continuously have some asynchronous and localized disturbance events.Tree fall gaps are the dominant form of such disturbances in these forests. Moist temperate forests dominated by Quercus leucotricophora in Garhwal were investigated for study. Ten random transect belts were established in a mixed broadleaved forest patch. The forest comprised of gaps, created by various natural processes. Gaps varied in size ranging from 48 to 589 m2. Microclimatic and edaphic variables of canopy gap and understorey areas were recorded to assess the parameters that influence gap phase regeneration. Forests of the studyarea comprised of gaps that varied in size and shape. Light intensity, soil moisture and soil temperature were prime micro-climatic variables influencing species recruitment in gaps.Species assemblage was recorded higher from gaps than forest understorey (20 and 17 tree species, respectively). Overall recruitment of tree species in understorey and canopy gaps was 3054 seedling ha-1 and 2277 saplings ha-1, respectively. The results obtained during our study show that gap formation process in moist temperate forests of Garhwal promotes a strong but temporary variations in microclimatic environment. This heterogeneity factor determines the biological diversity but needs more long term systematic research in Garhwal for better understanding.

Tree-Fall Gaps and Regeneration in Old-Growth Cross Timbers Forests

ABSTRACT Cross Timbers forests of south-central North America contain large expanses of relatively undisturbed old-growth forest where gap-phase regeneration is the main mode of canopy replacement. These forests are threatened by fire suppression, overgrazing, invasive species, global climate change, and urban development. To characterize dynamics of stand development and learn whether canopy trees lost in tree-fall gaps were being replaced by trees of the same species, we conducted a study of tree-fall gaps and their regeneration in three widely separated Oklahoma Cross Timbers forests. Eleven species were found in the forest canopy and three species dominated: post oak (Quercus stellata) (76%), blackjack oak (Q. marilandica) (7%), and black hickory (Carya texana) (10%). Although gaps were small (13–30 m2) resulting from the death of one to two trees, regeneration did not appear to depend on gap size. There was abundant regeneration even in the understory of the closed canopy; most likely much of it was ...

Modelo de ciclo forestal para la gestión sostenible de los bosques de Pinus nigra subsp. salzmannii deducido a partir de datos dendrocronológicos

Tíscar, P.A. 2015. Model of forest cycle for the sustainable management of Pinus nigra subsp. salzmannii obtained from dendrochronological data. Ecosistemas 24(2): 30-36. Doi.: 10.7818/ECOS.2015.24-2.05. The article proposes a model of forest cycle for pinewoods of Spanish black pine (Pinus nigra subsp. salzmannii). Five developmental phases were defined: innovation, early aggradation, late aggradation, biostatic and degradation. Phases were characterized from dendrochronological data obtained from 78 trees sampled in a 10x680 m2 transect located in Cazorla mountain range (SE Spain). Forest structure and Pinus nigra regeneration mode were also described from this transect. A high structural heterogeneity was observed at small scale. Pine regeneration was observed to occur according to the gap-phase regeneration mode. Late phases of the forest cycle were characterized with less exactness than the initial ones, probably because of changes in tree density during the forest history. The length of the proposed model of forest cycle was estimated as 500 years and the minimum equilibrium area as 20 hectares. These data are of interest for the sustainable management of Pinus nigra forests.

Plant Species Diversity in Unmanaged Moist Deciduous Forest of Northern India

The present study examines species recovery and change in community composition four decades after the management plan completely constrained all silvi-cultural activities in Doon Valley (India) moist deciduous sal forests ( Shorea robusta ). These forests experienced intensive commercial logging for an extended period (> 100 years). To discontinue disinte-gration and improve the diversity and regeneration, these were declared protective and consequently all silvicultural activities were abandoned. For this, spe-cies richness and regeneration were studied in the con-text of overstorey structure, employing nested quadrat method. Out of 130 species reported in the earliest-most study from these forests, only 68 species were recorded here. Change in community composition has taken place with Mallotus philippensis becoming do-minant in one community; this association is new for these forests. Effect of overstorey structure was noti-ceable, highest species richness and diversity were in-creasing with a decrease in tree density and basal area. These forests showed impaired regeneration progression; for all the groups there was a wide gap between the seedlings and saplings conversion to ad-vance stages. Prospects of recovery are fair as several tree species were reported in juvenile stages with ade-quate density. Results demonstrated that conversion of forests having a long history of exploitation to pro-tected forest is initially good, but for successful recov-ery, after a restitution time, it is desirable to emulate intermediate disturbance by selective harvesting of old and malformed trees. This will initiate gap-phase regeneration and channelize resources to lower dia-meter class trees to develop.

Repeated prescribed fires alter gap-phase regeneration in mixed-oak forests

Oak dominance is declining in the central hardwoods region, as canopy oaks are being replaced by shade-tolerant trees that are abundant in the understory of mature stands. Although prescribed fire ...

Composition, structure, and dendroecology of an old-growth Quercus forest on the tablelands of the Cumberland Plateau, USA

Forest reconstructions provide information on the processes that influence forest development and successional patterns. In this study, we quantified woody species composition, stand structure, and radial growth patterns of individual Quercus trees to document the processes that shaped a forest on the Cumberland Plateau in Tennessee over the past three centuries. The oldest trees on the site established in the late-1600s. The forest was dominated by Quercus alba, but Acer rubrum and Oxydendrum arboreum were the most abundant species in small size and young age classes. Quercus recruitment was continuous over the past three centuries whereas Pinus established in the late-1800s and early-1900s and Acer established in the 1940s. Most overstory Quercus recruited via gap-phase regeneration and ca. one-third established under a closed canopy and were suppressed for up to 80 years prior to overstory release. Pinus recruitment corresponded to stand-wide canopy disturbance while Acer recruitment had no relationship to overstory removal. Over the last three centuries, we contend Quercus has been the dominant genus with Pinus restricted to patches that corresponded to canopy disturbances. The recent profusion of Acer in the understory will likely inhibit regeneration of Pinus and Quercus. Indeed, the composition of the overstory and understory were dissimilar and under the current disturbance regime, the A. rubrum component should increase. Gap-scale disturbance frequency has remained relatively stable since the mid-1700s. However, the frequency of stand-wide canopy disturbance events has decreased since the mid-1800s and the last initiated in 1903.

Regeneration niches and functional traits of three common species in subtropical dune forest

South African coastal dune forests are young, highly disturbed subtropical communities where conventional models of forest dynamics may be challenged. We tested predictions from the gap-phase regeneration model by comparing seedlings of three common species representing contrasting regeneration strategies: Acacia karroo as a ruderal, Celtis africana as a coloniser of forest gaps, and Diospyros natalensis as a late-successional species. We grew seedlings under contrasting light and nitrogen levels in a greenhouse and in the field for 1 year to compare their growth and survival rates, allocation and photosynthetic traits. Species’ growth rates generally followed the expected order: Acacia>Celtis>Diospyros, but Acacia responded strongly to light and Celtis responded strongly to nitrogen, leading to cross-overs in growth rates. The plasticity of allocation and photosynthesis did not clearly differentiate the strategies, although it was greater in the light-demanding species. Acacia and Celtis tended to survive better in Acacia stands than in forest plots. Leaf-level light compensation points (LCPs) were similar for the three species in most conditions, but auxiliary data suggest Diospyros has a lower whole-plant LCP than Acacia. Growth rates and LCPs were lower than most of those reported for primary-forest species in the literature, suggesting an unusual degree of shade-tolerance in this habitat. We discuss reasons why variation in shade-tolerance may be less important here than in the prevailing model for forest regeneration and suggest other biotic factors that may help differentiate regeneration niches.

Complex spatial structure in a population of Didymopanax pittieri, a tree of wind-exposed lower montane rain forest

Didymopanax pittieri is a common shade-intolerant tree colonizing treefall gaps in the elfin forests on windswept ridgecrests in the lower montane rain forests of the Cordillera de Tilaran, Costa Rica. All D. pittieri taller than >0.5 m in a 5.2-ha elfin forested portion of a gridded study watershed in the Monteverde Cloud Forest Preserve were located, mapped, and measured. This local population of D. pittieri is spatially inhomogeneous, in that density increases with increasing wind exposure; D. pittieri are more abundant near ridge crests than lower on windward slopes. The important and ubiquitous phenomenon of spatial inhomogeneity in population density is addressed and corrected for in spatial analyses by the application of the inhomogeneous version of Ripley’s K. The spatial patterns of four size classes of D. pittieri ( 20 cm dbh) were investigated. Within the large-scale trend in density driven by wind exposure, D. pittieri saplings are clumped at the scale of treefall gaps and at the scale of patches of aggregated gaps. D. pittieri 5–10 cm dbh are randomly distributed, apparently due to competitive thinning of sapling clumps during the early stages of gap-phase regeneration. D. pittieri larger than 10 cm dbh are overdispersed at a scale larger than that of patches of gaps. Natural disturbance can influence the distribution of shade intolerant tree populations at several different spatial scales, and can have discordant effects at different life history stages.

Tree growth and age in an ancient Hawaiian wet forest: vegetation dynamics at two spatial scales

Abstract:In this study I document the growth rate and age of trees in an old-growth montane Hawaiian wet forest and use these results to evaluate the cyclic succession model for forest dynamics. I used two methods to estimate the age of trees – the crown-class model and radiocarbon dating. Over 6000 trees belonging to eight species were tagged and measured over 7 y on Hawaii Island. Growth rates for the dominant tree (Metrosideros polymorpha) were relatively low (mean = 1.3 mm y−1) and varied with tree size and crown class. 14C-based age estimates for 27 M. polymorpha trees loosely corroborated estimates based on the crown-class method. The oldest tree dated by 14C had a median age of 647 y BP, placing it among the oldest documented angiosperm trees in the northern hemisphere. 14C dating revealed that the upper canopy may be comprised of three distinct age groups of M. polymorpha trees of similar size, with the median age of each group separated by 200–250 y. The high density of large, very old trees in multiple groups is unusual for a tropical forest and indicates that forest development may occur through gap-phase regeneration at a fine scale and stand-level mortality at a coarser scale.

Gap phase regeneration recruitment of mixed conifer-broadleaf forests in Wolong Nature Reserve

Wolong Nature Reserve is the largest reserve for protecting the endangered wild giant panda. Due to historical factors, even in many sections of the core protection area, the forests have been seriously destroyed and natural forests are poorly restored. However, the relative importance of the determinants for recruitment of communities under disturbance is rarely explored. In our study the endogenous and exterior factors in a forest gap that affect the conifer-broad-leaved mixed forest regeneration were investigated near Wuyipeng, one of the observation stations at Wolong, to explore which determinant had the greatest effect on gap regeneration and to discover the recruitment of seedling establishment in forest gaps. With a linear sampling method, environmental factors, gap characteristics and recruitment of new individuals were measured and examined in every forest gap along three sampling lines. Data of environmental factors in the gaps were collected for a Pearson correlation analysis in order to explore the disturbance and preprocessed characteristics of the gaps, using principal component analysis in SPSS. Correlation analysis was applied to further explore the relationship between changes in the gaps and the response of the regenerating seedlings. The results show that a range of natural and human disturbances affected the pattern and characteristics of the forest gaps in this area. The richness in the composition of the seedlings was higher than that of gap makers, but the order of dominance of the composition was different between seedlings and gap makers. The success of dominant species in establishing themselves was affected by different environmental factors. For instance, the establishment of Betula spp. was correlated significantly with topographic factors, while that of Abies faxoniana was affected by soil characteristics and that of Rhododendron spp. correlated significantly with topographic factors and characteristics of gap makers. Moreover, all the biodiversity indices of regenerating seedlings were significantly correlated with environmental principle components mostly reflecting soil properties. From this we can infer that soil characteristics are the most important factors affecting the regeneration of dominant species and seedling diversity under gap disturbances.

Deer prevent western redcedar ( Thuya plicata) regeneration in old-growth forests of Haida Gwaii: Is there a potential for recovery?

The current increase in deer populations in many forests has fostered a growing concern about their impact on forest ecology. Sitka black-tailed deer ( Odocoileus hemionus sitchensis) were introduced to Haida Gwaii (British Columbia, Canada) in the late 19th century, and they have dramatically affected the regeneration of woody species in both old- and second-growth forests since then. The lack of recruitment in western redcedar ( Thuja plicata) in old-growth forests has been attributed to deer. The objectives of this study were to (1) experimentally confirm that deer browsing causes a lack of western redcedar recruitment and (2) assess the potential for and speed of recovery after a prolonged exclusion of deer. We installed a set of 20 enclosures and monitored them over a period of 8 years from 1997 to 2005. We compared temporal changes in redcedar cover and in the survival and growth of marked seedlings in plots that were or were not accessible to deer. Redcedar cover in the vegetation layer accessible to deer was generally low (from 3 to 5%) but higher inside the enclosures (an average difference of 2.3%). Protected seedlings survived better, were higher, presented more leafed shoots, and had less stems than unprotected individuals, features that suggest that deer were key to the lack of regeneration. However, growth was very slow (protected marked seedlings grew 2.5 cm on average in 8 years) and, under the current conditions, the time required for a protected seedling to escape deer would probably take over two decades. This very slow growth rate under closed canopy conditions probably reflects a gap-phase regeneration strategy and/or sensitivity to competition with other woody species. The combination of a very slow growth with a high palatability and a lack of physical defences, in contrast to the other dominant conifers in this ecosystem, probably explain why redcedar regeneration can be eliminated from old-growth forest by abundant deer populations.

An ecosystem model for tropical forest disturbance and selective logging

A new three‐dimensional version of the Carnegie‐Ames‐Stanford Approach (CASA) ecosystem model (CASA‐3D) was developed to simulate regional carbon cycling in tropical forest ecosystems after disturbances such as logging. CASA‐3D has the following new features: (1) an alternative approach for calculating absorbed photosynthetically active radiation (APAR) using new high‐resolution satellite images of forest canopy gap fraction; (2) a pulse disturbance module to modify aboveground carbon pools following forest disturbance; (3) a regrowth module that simulates changes in community composition by considering gap phase regeneration; and (4) a radiative transfer module to simulate the dynamic three‐dimensional light environment above the canopy and within gaps after forest disturbance. The model was calibrated with and tested against field observations from experimental logging plots in the Large‐scale Biosphere Atmosphere Experiment in Amazonia (LBA) project. The sensitivity of key model parameters was evaluated using Monte Carlo simulations, and the uncertainties in simulated NPP and respiration associated with model parameters and meteorological variables were assessed. We found that selective logging causes changes in forest architecture and composition that result in a cascading set of impacts on the carbon cycling of rainforest ecosystems. Our model sensitivity and uncertainty analyses also highlight the paramount importance of measuring changes in canopy gap fraction from satellite data, as well as canopy light‐use efficiency from ecophysiological measurements, to understand the role of forest disturbance on landscape and regional carbon cycling in tropical forests. In sum, our study suggests that CASA‐3D may be suitable for regional‐scale applications to assess the large‐scale effects of selective logging, to provide guidance for forest management, and to understand the role of forest disturbance in regional and global climate studies.

The role of gap phase processes in the biomass dynamics of tropical forests

The responses of tropical forests to global anthropogenic disturbances remain poorly understood. Above-ground woody biomass in some tropical forest plots has increased over the past several decades, potentially reflecting a widespread response to increased resource availability, for example, due to elevated atmospheric CO2 and/or nutrient deposition. However, previous studies of biomass dynamics have not accounted for natural patterns of disturbance and gap phase regeneration, making it difficult to quantify the importance of environmental changes. Using spatially explicit census data from large (50 ha) inventory plots, we investigated the influence of gap phase processes on the biomass dynamics of four 'old-growth' tropical forests (Barro Colorado Island (BCI), Panama; Pasoh and Lambir, Malaysia; and Huai Kha Khaeng (HKK), Thailand). We show that biomass increases were gradual and concentrated in earlier-phase forest patches, while biomass losses were generally of greater magnitude but concentrated in rarer later-phase patches. We then estimate the rate of biomass change at each site independent of gap phase dynamics using reduced major axis regressions and ANCOVA tests. Above-ground woody biomass increased significantly at Pasoh (+0.72% yr(-1)) and decreased at HKK (-0.56% yr(-1)) independent of changes in gap phase but remained stable at both BCI and Lambir. We conclude that gap phase processes play an important role in the biomass dynamics of tropical forests, and that quantifying the role of gap phase processes will help improve our understanding of the factors driving changes in forest biomass as well as their place in the global carbon budget.

Tree regeneration and microclimate in a liana and bamboo-dominated semideciduous Atlantic Forest

We assessed the effect of native bamboo and lianas on microclimate, tree regeneration and forest structure in a semi-deciduous Atlantic Forest subjected to selective timber extraction during the last century. We hypothetized that bamboo and liana cutting would increase incoming solar radiation in the understory promoting establishment and survival of pioneer and light-requiring canopy tree species. A manipulative experiment consisting of bamboo and liana cutting was performed in a native forest stand in northeastern Argentina. In three permanent 1-ha plots bamboo and lianas were cut and allowed to decompose in situ, while other three plots were used as a control treatment. We measured solar radiation reaching the understory, soil water availability and air temperature in both bamboo and liana cutting and control plots. Tree sapling abundance and richness, stand basal area, bamboo density, and cover of lianas, herbs, shrubs, fallen trees and branches were also determined. We performed multivariate analyses to relate tree sapling abundance and richness with biotic and abiotic factors. Bamboo and liana cutting increased by 100% the solar radiation reaching the understory. The fraction of solar radiation transmitted at 0.7 m height above ground in control and treated plots was 0.1 and 0.2, respectively. Minimum soil matric potentials after a severe dry spell were less than −2 MPa. Soil water availability was higher under closed-canopy in the treated plots because liana transpiration was prevented by cutting. Although bamboo and liana cutting increased incoming solar radiation, tree seedling and sapling abundance of pioneer and light-demanding species was not improved by the treatment. Instead, an increased abundance of herbaceous plants was observed in gaps and open canopy areas (i.e., sites with amounts of herb cover greater than 75% represented the 11 and 2% of the total number of sites in treated and control plots, respectively). Sapling survival and growth rates, on the other hand, appeared to be promoted by bamboo and liana cutting. Bamboo inhibited tree sapling abundance and richness in gaps, whereas tree basal area had a positive effect. In the semideciduous Atlantic Forest, native bamboos modify gap phase regeneration, and may affect canopy cover and forest composition in the long term. Post-logging management techniques are needed for sustainable timber production in these forest stands.

Changes in the stand structure (1975–2000) of coastal Banksia forest in the long absence of fire

Abstract Revisitation studies enable long‐term changes in vegetation to be deciphered and insights into plant community succession to be gained. This is particularly important when assessing the effects of fire exclusion in ecosystems where fire is thought to have once been common. Using two adjacent coastal Banksia integrifolia forest stands in southern Victoria, Australia initially surveyed in 1975 by Hazard and Parsons, we document the changes that occurred in the stand structure between 1975 and 2000. Western Park (WP) has now remained unburnt for over 100 years while Cerberus Naval Base (CNB) was most recently burnt in 1942. Banksia integrifolia densities have decreased at both sites over the 25‐years period by an average of 42–77%, as have other coastal native shrubs (e.g. Leptospermum laevigatum, Leucopogon parviflorus). Trees at WP appear to have died due to old age while mortality at CNB is presumed to be due to stand thinning in response to intense competition for light. Successful recruitment by Banksia has been minimal; trees less than 9 cm girth over bark at breast height (GBBH) were absent at CNB while no trees <19 cm GBBH were observed at WP. The long‐term absence of disturbance such as fire is suspected to be one of the causes of regeneration failure of the stand at WP. Gap phase regeneration is not apparent in B. integrifolia and hence, long‐term succession to a more grassy community is likely when fire is excluded for long periods.

Effective height development of four co-occurring species in the gap-phase regeneration of Douglas fir monocultures under nature-oriented conversion

Natural regeneration in gaps in Douglas fir forest stands in the Netherlands mainly consists of Betula pendula (Roth.), Pinus sylvestris (L.), Larix kaempferi (Carr.), and Pseudotsuga menziesii (Mirb. Franco). Even though these species are well known, the autogenic development of these species in an unmanaged plant community falls outside of traditional silvicultural experience. We therefore present an explorative study, aimed to map out differences between these species under conditions of co-occurrence, and develop hypotheses on the further development of these sapling communities. We focused on differences in height, and particularly the architectural contribution to height. We analyzed interspecific differences in the height–mass and height–DBH relationship, biomass partitioning, and slenderness for a total of 177 saplings up to 13.7 cm DBH and 11.8 m high. Average annual height and diameter growth rates of an additional 48 saplings are presented for comparison with the static architectural data. Betula had a high stem biomass, high stem slenderness, and low leaf mass. The reverse was true for Pseudotsuga. Larix behaved as an intermediate species. Pinus however deviated from the classical pioneer–climax dichotomy in having a low slenderness and low height per unit biomass while being a highly light-demanding species. The static height-mass relationship shows a similar species ranking when compared to average annual height growth rates, but not when compared to diameter growth rates. This underlines the importance of a species’ architecture for its height development and suggesting a predictable stratification between species. Based on the results regarding species’ stratification in heights and a priori information on light demand, it is hypothesized that in the studied gap-phase regeneration Betula, Larix and Pseudotsuga will partition the available light. Pinus however will be overtopped and given its need for high-light environments, is expected to be competitively excluded.

Effects of light acclimation on the photosynthesis, growth, and biomass allocation in American chestnut ( Castanea dentata) seedlings

American chestnut ( Castanea dentata) is currently regarded as functionally extinct because of chestnut blight. To reintroduce blight-resistant American chestnut back to its historic range, it is imperative to understand the silvics and silviculture of the species. In an outdoor rainout shelter, we grew American chestnut seedlings at four levels of irradiance (4, 12, 32 and 100% of full sunlight) to examine how light intensity affects photosynthesis, growth, and biomass allocation. Net photosynthetic rate increased linearly with increasing irradiance while instantaneous water use efficiency peaked at 32% full sunlight, when seedlings were measured at their acclimated irradiance level. Height and diameter increased with increasing irradiance. However, seedlings only grew laterally under 4% full sunlight. Total biomass increased linearly with increasing irradiance and root to shoot ratio was lowest under 4 and 12% full sunlight. Regardless of irradiance level, >70% of total biomass was allocated to shoot growth. With increasing shade, specific leaf area significantly increased. These observed physiological and morphological light acclimation characteristics indicate that American chestnut is shade tolerant, which partially explains why the species has persisted in the understory for almost a century. The shade-tolerance and fast growing characteristics suggest that an underplanting-and-release or gap-phase regeneration approach would be a suitable silvicultural alternative to a clearcut-and-planting approach for the reintroduction of blight-resistant American chestnut.

Structure, dynamics and dendroecology of an old-growth Fagus forest in the Apennines

Question: Which are the structural attributes and the history of old-growth Fagus forest in Mediterranean montane environments? What are the processes underlying their structural organization? Are these forests stable in time and how does spatial scale affect our assessment of stability? How do these forests compare to other temperate deciduous old-growth forests? Location: 1600-1850 m a.s.l., Fagus forest near the tree line, central Apennines, Italy. Methods: An old-growth Fagus forest was studied following historical, structural and dendroecological approaches. History of forest cover changes was analysed using aerial photographs taken in 1945, 1954, 1985 and 1994. The structural analysis was carried out in the primary old-growth portion of the forest using 18 circular and two rectangular plots. Dendroecological analyses were conducted on 32 dominant or co-dominant trees. Results: These primary old-growth Fagus remnants consist of four patches that escaped logging after World War II. Both living and dead tree components are within the range of structural attributes recognized for old-growth in temperate biomes. Dendroecological analyses revealed the roles of disturbance, competition and climate in structuring the forest. We also identified a persistent Fagus community in which gap-phase regeneration has led to a mono-specific multi-aged stand at spatial scales of a few hectares, characterized by a rotatedsigmoid diameter distribution. Conclusion: Even at the relatively small spatial scale of this study, high-elevation Apennine Fagus forests can maintain structural characteristics consistent with those of old-growth temperate forests. These results are important for managing oldgrowth forests in the Mediterranean montane biome.