Restoration Of Pine Forests Research Articles

Changes in Soil Physicochemical Properties and Fungal Communities Following a Forest Fire in the Pine Forest of Uljin, Republic of Korea

Soil samples from the rhizosphere of pine (Pinus densiflora) stands in the fire-disturbed Uljin forest were collected to analyze their physicochemical properties and fungal communities. In the burned area, soil pH decreased by 0.56, and organic matter content decreased by 0.32%p compared to the undisturbed area. Fungal community analysis revealed that all alpha diversity indices decreased in the burned area, but there were no differences according to fire severity. Soil pH, available phosphorus, and total nitrogen showed a positive correlation with the alpha diversity. Additionally, beta diversity analysis also indicated significant differences in the fungal communities between the burned area and the control sites (p value = 0.031). The changes in fungal communities were considered to be influenced by the decline in the order Atheliales, genus Russula, and genus Trechispora. A prediction analysis of the functional traits of fungi showed that the number of fungi involved in nutrient absorption and decomposition decreased in the burned area. It seems that the soil restoration of pine forests is progressing very slowly, as the soil fungi related to nutrient absorption by pine trees have not recovered even 18 months after the forest fire. Therefore, it is necessary to monitor continuous fungal communities in pine forest restoration after a forest fire to determine forest ecosystem restoration success and stabilization.

Macrofauna and Organic Matter in Postagrogenic Sandy Soils at the NW Smolensk Region (Russia)

Natural reforestation on the abandoned arable lands is one of the characteristic processes that triggers the transformation of soils, accompanied by the change in the abundance, biomass, and taxonomic structure of the soil macrofauna. The assessment of the restoration potential of the soil properties and soil macrofauna to the natural state, the duration of this period, the dynamics of soil organic carbon stocks, and the role of macrofauna in this process at different stages of post-agrogenic successions is relevant for prediction of changes in ecosystem components and their role in the storage of organic carbon under various land use scenarios. The work is based on the data on organic carbon reserves, morphological properties of soils, abundance, biomass and taxonomic structure of the soil macrofauna of arable lands, primary forests and 5 stages of pine forest restoration (fallow meadows and pine forests of different ages) at the Smolenskoye Poozerye National Park (Smolensk region). It was revealed that in the soils of the 85–100-year-old pine forests, signs of plowing are preserved in the form of the smooth lower boundary of the humus horizon. At the same time, signs of soil regradation appear already at the meadow stage and are expressed in the formation of a thin humus horizon penetrated by roots, which transforms further at the next stages. In the litter and mineral part of the soil, the carbon stocks change non-monotonically with a maximum at the meadow stage and a minimum in 70–80-year-old forests. By the age of 80, the stock of organic carbon in the mineral part of soils is almost restored to the background values. The composition of soil macrofauna changes drastically during the transition from meadow to forest communities. At the initial stages (in agrocenoses and fallow meadows), the fauna of mineral soil horizons predominates: endogeic earthworms and larvae of lamellar beetles. Further, the fauna of organic horizons is restored, among which there is a high proportion of saprophages – epigeic and epi-endogeic earthworms, which contribute to the differentiation of litter. The biomass of saprophages has a negative correlation with the carbon reserves in the mineral part of forest soils, the thickness and reserves of organic carbon in the litter, and a positive correlation with the share of the easily decomposable litter fraction.

Characterizing the Change of Annual Cone Production in Longleaf Pine Forests

Sporadic cone (or seed) production challenges longleaf pine forest restoration. Characterizing annual cone production change from long-term monitored data provides functional information on the foundational species of this imperiled ecosystem. In this study, permutation entropy (PE) and phase change were used to analyze longleaf pine annual cone production based on cone counts from four sites (Escambia Experimental Forest, Blackwater River State Forest, The Jones Center at Ichauway, and Sandhills State Forest). PE is an analytical tool to measure the complexity of a dynamic system while phase change characterizes the stage of self-organization. Results indicate that PE at each site was close to 1.0 (largely random changes in annual cone production) and generally increased with time. The positive association between the permutation entropy of cone production and average air temperature at different times was significant at two sites (Blackwater River State Forest and The Jones Center at Ichauway). The frequency distribution of phases (e.g., Poor (P), Fair (F), Good (G), Bumper (B)) in cone production followed negative power laws. Phase P could transition to any stage, but more than 50% remained in P across sites. For phase G, it would revert to P more than 50% of the time. Phase B would shift to P, except at Sandhills State Forest. The average lasting time of phase P was approximately 3.7 years. The overall relationship between the interval time of phase B and cone production was not statistically significant. Similarly, the overall relationship between cone production in phase B and the phase change times between consecutive B phases was not statistically significant. These results provide information on the ecological complexity of cone (or seed) production. Our methods can be helpful for estimating the occurrence of bumper cone (or seed) production, the lasting period between phase changes, and providing a tool for predicting natural regeneration potential over time for longleaf pine and other tree species (e.g., masting species).

Post-fire restoration of pine forests in the Badary area, Tunkinskiy National Park, Russia

A morphological variety of pyrogenic transformations characterises burnt areas of the Badary area of the Tunkinskiy National Park (Russia), from heavily damaged areas with a partially remained forest stand to bare spaces of tens of square metres. This enabled us to study the dynamics of the post-fire reproduction of Pinus sylvestris (hereinafter – pine) forests in areas with various environmental conditions. The main goal of our study was to determine the nature of the pyrogenic transformation of ecosystems and to evaluate the success of the forest reproduction. The studies were based on the geobotanical monitoring in two burnt-out areas, differing in the degree and area of wildfire damage due to a creeping fire in 2010. Between 2014 and 2020, we considered the multi-temporal specificity of the species composition of the forest stand, shrub layer, and plant communities. The emergence of the first shoots of undergrowth and new growth has been recorded. The projective cover and the dynamics of the species abundance in all forest layers were fixed. The analysis of the natural reforestation dynamics revealed a similarity of the main geobotanical indicators. Pine seedlings dominated in the undergrowth of the study sites, with a small proportion of Betula pendula. The shrub layer consisted of Rosa acicularis. Rhododendron dauricum has been found there only at the late stage of the study. In the herbaceous layer, the largest proportion was represented by meadow species, with a small participation of forest plants. Differences were revealed during the emergence of first seedlings of undergrowth and new growth, as well as in the size of projective cover of species in all forest layers. The first pine seedlings on a heavily burnt-out study plot were recorded a year earlier than on a less transformed plot. Nevertheless, the height increment and the projective cover of the undergrowth were significantly higher on the burnt-out area of a medium damage degree. On the heavily fire-damaged area, we observed pine seedlings planted by the staff of the Tunkinskiy National Park. A satisfactory rate of seedling survival at the initial stage and further deceleration of growth parameters have been noted. The obtained results indicate the reforestation success and, therefore, a favourable forecast of post-fire recovery of light-coniferous forests in the Badary area of the Tunkinskiy National Park.

Stages of Restoration of Components of Post-Agrogenic Pine Forest Ecosystems at the National Park “Smolensk Lakeland”

Rural depopulation in Russia was accompanied by the abandonment of arable lands and natural reforestation. The aim of the work was to study soils and phytocenoses of six stages of pine forest restoration on rocks with coarse granulometric composition in the north-west of Smolensk region. The research was carried out at 18 key sites, characterizing 6 stages in triplicates. Under agrocenoses and one-year-old fallow lands we found agrozemes (Arenosols (Aric)) with a thick arable layer and a minimum abundance and biomass of macrofauna, represented mainly by phytophages and saprophages. At the 2nd stage of fallow meadows, grey-humus soils (Arenosols) and sod-podzols postagrogenic (Entic Podzols) were found with unchanged morphological properties in comparison with the first stage. Here, the biomass of macrofauna is maximal due to intensive invasion of open biotopes by insects. Young (up to 30 years old) pine forests grew on similar to the Stage 2 regraded soils. During 10 years of a forest growth, litter and protohumus regrading horizons were formed. In middle-aged (70–80 years old) pine forests on sod-podburs post-agrogenic regraded (Entic Podzols), signs of an eluvial process are manifested. Macrofauna is characterized by a decrease in the biomass of a litter population. In forests older than 80 years, decay of pine stands with the formation of complex spruce forests have begun. In soils, even lower boundary of old-fallow horizon disappears without podzolic horizon formation. Here, the maximum biomass of litter macrofauna is revealed. The final stage is shrubby (lingonberry)-green-moss pine forests older than 90 years growing on podzols (Albic Podzols) with remains of old-fallow horizon. Among macrofauna, litter macrofauna prevail in terms of a biomass, but the biomass is lower than in the previous stage. Due to the different degree of morphological manifestation of the alfegumus process, the fifth and sixth stages can be considered as variants of the development of post-agrogenic soils under pine forests.

Forest restoration increases isolated wetland hydroperiod: a long‐term case study

AbstractGeographically isolated wetlands (GIWs) are well known as “hotspots” for biodiversity and other ecosystem services, making their value on landscapes disproportionate to the area they occupy. GIWs are dependent on regular cycles of inundation and drying, which makes hydrology a primary controlling variable for sustaining functions and associated ecosystem services. Although human activity has degraded GIWs in many regions, relatively little work has focused on upland management as a way of sustaining, or even improving, GIW structure and function. We present a case study of longleaf pine forest restoration, by hardwood removal, on the characteristics of a wetland hydroperiod over a 10‐year study. Our study wetland, W‐51, is 0.89 ha with a catchment area of 31.2 ha located on a ~11,400‐ha private preserve in Baker County, Georgia (31.250° N, 84.495° W). Beginning in 2006, continuous water level and climate data were recorded in the wetland and adjacent well transects across the wetland catchment. In autumn 2009, hardwoods were removed or deadened in the catchment resulting in a 37% reduction in tree cover. The effects on the hydrologic system were measured through 2016 by examining pre‐ and post‐removal water levels, water yield ecosystem (WYe), and standardized recession rates (RRstd). The study included periods of above and below normal rainfall. Generally, wetland hydroperiods began in December and ended in May, but varied with rainfall pattern and amount. Hardwood removal increased WYe and decreased RRstd resulting in greater catchment water availability as reflected in water levels. Hardwood removal affected both the ascending and recessing limbs of wetland hydroperiods, substantially increasing the availability of ponded water in the wetland. Our results quantify changes in wetland hydrologic characteristics associated with forest management activities, which appear to have reduced forest water demand. Our study was a management case study, limited in scope but conducted in a realistic setting. More extensive studies (paired, replicated designs) are needed to better understand the implications at both the local scale, that is, managing critical aquatic habitat for wildlife populations, and at the regional scale, that is, providing support for landscape‐scale connectivity and water yields.

Post‐fire restoration with contour‐felled log debris increases early recruitment of Spanish black pine (Pinus nigra Arn. ssp. salzmannii) in Mediterranean forests

Post‐fire environmental conditions can heavily influence the natural regeneration of pine species in Mediterranean forests. Therefore, enhancing post‐fire recovery of pine species is fundamental for effective ecological restoration of Mediterranean forests. In this study, the effects of a post‐fire restoration treatment on the seedling emergence and survival of Spanish black pine (Pinus nigra Arn. ssp. salzmannii) were investigated under a treatment consisting of manual cut of burnt tree canopies placed on the soil surface with their tree branches, following contour lines (contour‐felled log debris, CFD) in comparison with a control site at plot scale. Both CFD and control plots were tested on three slope gradients and two experimental conditions, that is, protected vs. non‐protected seeds. The initial seedling recruitment of Spanish black pine was improved by CFD treatment and seed protection, specifically through increased survival of emergent seedlings by about 10 and 15 times, respectively, compared to control. Seedling emergence was not significantly different between the treatments or controls; however, the highest seedling emergence in the study (18.9 ± 14.9%) was recorded under the least severe drought conditions. The study demonstrates that post‐fire CFD and seed protection treatments can be favorable for supporting ecological restoration of these pine forests. However, the environmental conditions are important drivers for the success of these strategies. Since droughts are expected to be more frequent in the upcoming years, post‐fire management strategies that include treatments like CFD and seed protection can be useful in the ecological restoration of Mediterranean pine forests.

Prospects for artificial restoration of pine forests in the Republic of Bashkortostan

Prospects for artificial restoration of pine forests in the Republic of Bashkortostan

UAV‐derived estimates of forest structure to inform ponderosa pine forest restoration

AbstractRestoring forest ecosystems has become an increasingly high priority for land managers across the American West. Millions of hectares of forest are in need of drastic yet strategic reductions in density (e.g., basal area). Meeting the restoration and management goals requires quantifying metrics of vertical and horizontal forest structure, which has relied upon field‐based measurements, manned airborne or satellite remote sensing datasets. We used unmanned aerial vehicle (UAV) image‐derived Structure‐from‐Motion (SfM) models and high‐resolution multispectral orthoimagery in this study to quantify vertical and horizontal forest structure at both the fine‐ (<4 ha) and mid‐scales (4–400 ha) across a forest density gradient. We then used these forest structure estimates to assess specific objectives of a forest restoration treatment. At the fine‐scale, we found that estimates of individual tree height and canopy diameter were most accurate in low‐density conditions, with accuracies degrading significantly in high‐density conditions. Mid‐scale estimates of canopy cover and forest density followed a similar pattern across the density gradient, demonstrating the effectiveness of UAV image‐derived estimates in low‐ to medium‐density conditions as well as the challenges associated with high‐density conditions. We found that post‐treatment conditions met a majority of the prescription objectives and demonstrate the UAV image application in quantifying changes from a mechanical thinning treatment. We provide a novel approach to forest restoration monitoring using UAV‐derived data, one that considers varying density conditions and spatial scales. Future research should consider a more spatially extensive sampling design, including different restoration treatments, as well as experimenting with different combinations of equipment, flight parameters, and data processing workflows.

Effect of Herbaceous Layer Interference on the Post-Fire Regeneration of a Serotinous Pine (Pinus pinaster Aiton) across Two Seedling Ages

Herbaceous vegetation is a major source of interference with the regeneration of woody species. This is particularly the case after forest fires, as a dense herbaceous layer usually regenerates naturally. Although the competitive effect of the herbaceous vegetation upon tree seedlings has been widely studied, there are still gaps in knowledge for management related to the effect of tree seedling age and size on the outcome of the interaction. In this study, we seek to determine the response of maritime pine (Pinus pinaster Aiton) seedlings to herbaceous competition at two different seedling ages. For that, two treatments of herbaceous competition were implemented, namely unweeded (no action around pine seedlings) and weeded (herbaceous cover removed around pine seedlings). Treatments were conducted twice (2 and 4 years after the fire), and we monitored seedling survival and growth at the end of each growing season. The treatments were implemented across three adjacent landscape units that differed in the management of burned wood and that are representative of common post-fire scenarios: no intervention, salvage logging, and an intermediate degree of intervention. Weeding increased seedling survival from 44.7% to 67.8% when seedlings were 2 years old, but had no effect for four-year-old seedlings, which showed 99% survival. Seedling growth also increased in the weeding treatment, but only slightly. Moreover, growth (and survival for two-year-old seedlings) was strongly correlated with initial seedling size, particularly in the case of two-year-old seedlings. Initial pine seedling height was strongly and positively correlated with the height of the herbaceous layer, supporting the existence of microsite features that promote plant growth above competitive effects. The results support that management actions conducive to foster post-fire pine forest restoration in this Mediterranean ecosystem should reduce herbaceous competition at early stages after fire (second or third year) and focus on larger seedlings.

Toward Sustainable Cultivation of Pinus occidentalis Swartz in Haiti: Effects of Alternative Growing Media and Containers on Seedling Growth and Foliar Chemistry

Haiti has suffered great losses from deforestation, with little forest cover remaining today. Current reforestation efforts focus on seedling quantity rather than quality. This study examined limitations to the production of high-quality seedlings of the endemic Hispaniolan pine (Pinus occidentalis Swartz). Recognizing the importance of applying sustainable development principles to pine forest restoration, the effects of growing media and container types on seedling growth were evaluated with the goal of developing a propagation protocol to produce high-quality seedlings using economically feasible nursery practices. With regard to growing media, seedlings grew best in compost-based media amended with sand. Topsoil, widely used in nurseries throughout Haiti, produced the smallest seedlings overall. Despite a low water holding capacity and limited manganese, compost-based media provided adequate levels of essential mineral nutrients (particularly nitrogen), which allowed for sufficient seedling nutrition. Seedling shoot and root growth, as well as the ratio of shoot biomass to root biomass, were greater in polybags relative to D40s. Results indicate that economically feasible improvements to existing nursery practices in Haiti can improve the early growth rates of P. occidentalis seedlings.

Managed Fire Frequency Significantly Influences the Litter Arthropod Community in Longleaf Pine Flatwoods.

Frequent prescribed burns are essential to pine forest restoration and management. Research studies have assessed effects of prescribed fire and burn frequency on plants and vertebrates, but impacts of fire on terrestrial invertebrate communities are still poorly understood. This case study investigated effects of burning frequency on species richness and community composition of social insects (ants, Hymenoptera: Formicidae and termites, Blattodea: Isoptera) in fire-managed Southern longleaf pine flatwoods in central Florida. Community response to different fire frequencies was assessed: burned annually, every 2 yr, or every 3 yr, 30 yr unburned and 75 yr unburned. Richness was similar across all treatments, but ant community composition and species density significantly differed between frequently burned (1, 2, and 3 yr) and long-unburned (30 and 75 yr) treatments. Long-unburned treatments had higher ant abundance, but the species present were less characteristic of open canopy longleaf pine habitat than ants in frequently burned treatments. The annual burn treatment differed from 2-yr burn in species density, but to a lesser degree. Exotic species abundance was highest in frequently burned sites; only native species were detected in the 75-yr unburned plot. The red imported fire ant, Solenopsis invicta Buren (Hymenoptera: Formicidae), was detected in all regularly burned plots but not in long-unburned sites. Frequent burning at this site increased habitat suitability for ant species adapted to the sunny, open canopy, and diverse niches characteristic of longleaf pine forest; however, regular fire disturbance also increased the likelihood of exotic ant species establishment.

Ponderosa Pine Forest Restoration Treatment Longevity: Implications of Regeneration on Fire Hazard

Restoration of pine forests has become a priority for managers who are beginning to embrace ideas of highly heterogeneous forest structures that potentially encourages high levels of regeneration. This study utilizes stem-mapped stands to assess how simulated regeneration timing and magnitude influence longevity of reduced fire behavior by linking growth and yield model outputs to a crown fire prediction model. Treatment longevity was assessed as return time to within 10% of pre-treatment predicted wind speeds for the onset of passive (Torching) and active (Crowning) crown fire behavior. Treatment longevity in terms of Torching and Crowning was reduced 5 years for every 550 and 150 seedlings ha−1, respectively. Introducing regeneration as a single pulse further reduced Torching treatment longevity 10 years compared to other regeneration distributions. Crowning treatment longevity increased at higher site indices, where a 6 m increase in site index increased longevity 4.5 year. This result was contrary to expectations that canopy openings after treatments would close faster on higher productivity sites. Additionally, Torching longevity was influenced by the rate of crown recession, were reducing the recession rate decreased longevity in areas with higher site indices. These dependencies highlight a need for research exploring stand development in heterogeneous sites.

Summer habitat use by adult female mule deer in a restoration-treated ponderosa pine forest

Across ponderosa pine—(Pinus ponderosa) dominated forests of northern Arizona, USA, large- scale restoration and fuels treatments are being implemented or planned to reduce wildfire threat and severity and improve ecosystem health. It is important to understand how these activities will affect animal populations, including species of economic and social importance, such as mule deer (Odocoileus hemionus). Forest treatments may improve foraging habitat for mule deer by opening forest canopy and stimulating shrub and herbaceous production, but also may reduce availability of day-bed sites. In this context, we used a generalized linear mixed-model approach and utilization distributions to estimate post-treatment relative intensity of summer (Apr-Sep) use of multiple habitat attributes by adult female mule deer on the Grand Canyon-Parashant National Monument in northern Arizona between 2003 and 2005. Based on 5,776 Global Positioning System collar locations from 10 individuals (� ¼ 580 locations/individual), we identified intensive use of areas that received a thin-and-burn treatment in the previous season, were located on gentle slopes, and were proximate to reliable water sources. Female mule deer likely selected thin-and-burn treatment areas to take advantage of increased forage abundance. Because thin-and-burn treatments did not remove Utah juniper (Juniperus osteosperma) or Gambel oak (Quercus gambelii), substantial shrub and mid- story vegetation cover remained post-treatment. Our results indicated the potential value of a mosaic approach to ponderosa pine forest restoration, where untreated areas, as well as treated areas that retain Gambel oak and juniper, are heterogeneously distributed across the landscape. This approach also would provide important concealment cover and forage after thin-and-burn and thin-only treatments. 2013 The Wildlife Society.

Preliminary Discussion on the Destruction and Restoration of Primary Korean Pine Forest in Maoershan Experimental Forest Farm of Northeast Forestry University

Preliminary Discussion on the Destruction and Restoration of Primary Korean Pine Forest in Maoershan Experimental Forest Farm of Northeast Forestry University

Native Plants Dominate Understory Vegetation Following Ponderosa Pine Forest Restoration Treatments

Dense ponderosa pine forests in the southwestern United States inhibit understory production and diversity and are susceptible to high-severity wildfire. Restoration treatments involving overstory thinning and prescribed burning are being implemented to increase understory productivity and diversity and to reduce the risk of severe wildfire. However, disturbances associated with treatments may favor invasion of nonnative species, and the severity of the disturbance may be related to the level of nonnative species establishment. We examined understory community composition, species richness, and plant cover responses to 3 stand-scale replicates of 4 different tree-thinning intensities. Restoration treatments altered the composition of the understory community regardless of thinning intensity. Understory richness and cover were highly variable among experimental blocks, but we observed strong trends of increasing richness and cover in the treated stands. Immediately following restoration treatments, nonnative species cover comprised 6% of the total cover where treatment-induced disturbances were the greatest. However, the initial increase in nonnative species did not persist and was reduced by half 6 years after treatment. Plant community composition was still in flux by the sixth year after treatment, indicating that continued monitoring is necessary for evaluating whether restoration targets are maintained over time.

Can pine forest restoration promote a diverse and abundant understory and simultaneously resist nonnative invasion?

An important goal of forest restoration is to increase native plant diversity and abundance. Thinning and burning treatments are a common method of reducing fire risk while simultaneously promoting understory production in ponderosa pine ( Pinus ponderosa) forests. In this study we examine the magnitude and direction of understory plant community recovery after thinning and burning restoration treatments in a ponderosa pine forest. Our objective was to determine if the post-treatment community was a diverse, abundant, and persistent assemblage of native species or if ecological restoration treatments resulted in nonnative species invasion. This project was initiated at the Grand Canyon-Parashant National Monument, Arizona, USA in 1997. We established four replicated blocks that spanned a gradient of soil types. Each block contained a control and a treated unit. Treated units were thinned to emulate pre-1870 forest stand conditions and prescribed-burned to reintroduce fire to a system that has not burned since ∼1870. We measured plant cover using the point-line intercept method and recorded species richness and composition on 0.05 ha belt transects. We examined the magnitude of treatment responses using Cohen's d effect size analysis. Changes in community composition were analyzed using nonmetric multidimensional scaling (NMS). Native plant species cover and richness increased in the thinned and burned areas compared to the controls. By the last year of the study, annual species comprised nearly 60% of the understory cover in the treatment units. Cheatgrass ( Bromus tectorum), a nonnative annual grass, spread into large areas of the treated units and became the dominant understory species on the study site. The ecological restoration treatments did promote a more diverse and abundant understory community in ponderosa pine forests. The disturbances generated by such treatments also promoted an invasion by an undesirable nonnative species. Our results demonstrate the need to minimize disturbances generated by restoration treatments and argue for the need to proactively facilitate the recovery of native species after treatment.

Canopy disturbance and tree recruitment over two centuries in a managed longleaf pine landscape

Disturbance history was reconstructed across an 11300ha managed longleaf pine (Pinus palustris Mill.) landscape in southwestern Georgia, USA. Our specific objectives were to: (i) determine forest age structure; (ii) reconstruct disturbance history through the relationship between canopy disturbance, tree recruitment and growth; and (iii) explore the relationship between canopy disturbance and climate. Age structure, canopy disturbance events and initial growth patterns at coring height were examined by randomly sampling 1260 trees in 70 1.3ha plots. Principal component analysis was used to group plots with similar age structures to gain insight into the dynamics between canopy disturbance and recruitment. Disturbance events were detected by large and rapid increases in radial growth. We tested the following hypothesis to investigate whether these growth increases could have been triggered by improved climatic conditions: precipitation and drought are positively correlated to radial growth releases. Only four stands (comprising <6% of the study area) had an even-aged structure. Further, tree recruitment prior to European settlement indicates that longleaf pine naturally recruited into areas 1.3ha or less, supporting early-20th century observations that the primary longleaf pine forest was uneven-aged. Contrary to our hypothesis, growing season precipitation and drought was significantly and negatively correlated with canopy disturbance (radial growth releases), which indicates that a reconstruction of disturbance history could proceed with some confidence. Most trees sampled were recruited at coring height from 1910 to 1935. Of the 67 canopy disturbances detected from 1910 to 1935, the average growth release ranged from 139 to 277% per half decade suggesting the occurrence of large canopy disturbances. Rapid initial growth patterns of young trees during these years show evidence of reduced overstory competition and support the detected disturbance intensity. Our reconstruction of stand dynamics is markedly similar to independent records of local oral and written history, which gives an additional set of evidence that the disturbance detection methodology used can be useful in open-canopied forests. Stands with multiple cohorts reveal a mix of continuous minor and major canopy disturbances leading to continual tree recruitment, suggesting their applicability as models for long-term forest management. The significant relationship between climate and disturbance in our data suggests that with the expected warming over the next 100 years, climatic impacts on stand dynamics should be incorporated into long-term longleaf pine forest restoration and management.

Restauración adaptable en la Meseta Purépecha, Michoacán, México: hacia un modelo de estados y transiciones

La restauración ecológica requiere de técnicas apropiadas que dirijan al sistema hacia las metas deseadas. La combinación de factores de disturbio antrópicos y naturales pueden crear estados en los cuales la sucesión secundaria no lleva al sistema hacia estadios maduros de la vegetación o lo hace de manera muy lenta. En el presente trabajo se desarrolla un esquema conceptual siguiendo los modelos de estados y transiciones para la restauración de bosques de pino en la Meseta Purépecha. Se sintetiza la información obtenida de un proyecto de restauración adaptable que se inició de manera colaborativa con la comunidad indígena de Nuevo San Juan Parangaricutiro en 2001. Se describe un estado posiblemente estable, los depósitos de ceniza volcánica conocidos como “arenales”, y se detallan algunas técnicas de restauración que permitirían su transición hacia el estado deseable dominado por Pinus pseudostrobus

Dynamics of ground vegetation after surface fires in hemiboreal Pinus sylvestris forests

The aim of this work was to investigate the changes of ground vegetation (field layer: mosses, lichens; ground layer: herbs, shrubs, tree seedlings and saplings) and regeneration of tree species in pine forests after surface fires. The study area was located in Southern part of Lithuania in hemiboreal zone of Europe. The field and ground vegetation was recorded in forest stands burned in 1992 and 1994–2002 and compared with the nearby control fire untouched areas. We selected five burned areas for each year (total 50 burned stands). Vegetation sampling was conducted during July and August 2003. For vegetation description in each stand we systematically placed twenty 1 m × 1 m plots. Mann–Whitney nonparametric test was used to identify significant differences in vegetation between burned and untouched areas. It was determined that species richness increased after fire. Early successional species such as Agrostis capillaris L., Calamagrostis epigejos (L.) Roth, Chamerion angustifolium (L.) Holub, Festuca ovina L. and Melampyrum pratense L. invaded in burned areas immediately after fire. Abundance of dominant species ( Vaccinium myrtillus L. and Vaccinium vitis-idaea L.) recovered after 5 years. Pioneer moss species ( Polytrichum piliferum Hedw. and Polytrichum juniperinum Hedw.) replaced late successional mosses ( Dicranum polysetum Sw., Dicranum scoparium Hedw., Hylocomium splendens (Hedw.) Schimp. and Pleurozium schreberi (Brit.) Mitt.). Species number in the shrub layer decreased. Juniperus communis L. was killed by fire. Amount of undergrowth decreased first 4 years after fire. Saplings of Picea abies (L.) Karst., disappeared at all. Fire stimulated regeneration of Pinus sylvestris L., especially first 4 years after fire. Herbaceous and dwarf shrubs recovered 5–6 years after fire, moss cover—9 years after fire. Differences in moss species composition still remained 11 years after fire. Main finding suggest that fire is favourable to biodiversity of pine forest ecosystems. Fires induce regeneration of pine trees and can be used for restoration of pine forest.