Long-Term Suppression of Hardwood Regeneration by Chinese Privet (Ligustrum sinense)

Native hardwood regeneration in the southeast United States is hindered by repeat disturbance events and the presence of invasive species. Our study aimed to determine the ability of native species in an unmanaged urban forest fragment to persist following high winds from hurricane Gustav in 2008 and subsequent salvage logging. In 2009, researchers estimated the density and composition of the regeneration and overstory trees as well as percent crown cover of invasive Chinese privet. Percent Chinese privet cover was visibly high, leading them to believe it may be inhibiting native hardwood establishment. Ten years later in 2019, we returned to the plots to take repeat measurements. Forest composition remains the same and privet crown cover remains high. There has been no increase in regenerating individuals, and overstory trees per hectare and basal area remains low. These results confirm that the heavy Chinese privet presence is persistent long term and will require management to promote reproduction of native overstory tree species.

Life Stage and Neighborhood-Dependent Survival of Longleaf Pine after Prescribed Fire

Determining mechanisms of plant establishment in ecological communities can be particularly difficult in disturbance-dominated ecosystems. Longleaf pine (Pinus palustris Mill.) and its associated plant community exemplify systems that evolved with disturbances, where frequent, widespread fires alter the population dynamics of longleaf pine within distinct life stages. We identified the primary biotic and environmental conditions that influence the survival of longleaf pine in this disturbance-dominated ecosystem. We combined data from recruitment surveys, tree censuses, dense lidar point clouds, and a forest-wide prescribed fire to examine the response of longleaf pine individuals to fire and biotic neighborhoods. We found that fire temperatures increased with increasing longleaf pine neighborhood basal area and decreased with higher oak densities. There was considerable variation in longleaf pine survival across life stages, with lowest survival probabilities occurring during the bolt stage and not in the earlier, more fire-resistant grass stage. Survival of grass-stage, bolt-stage, and sapling longleaf pines was negatively associated with basal area of neighboring longleaf pine and positively related to neighboring heterospecific tree density, primarily oaks (Quercus spp.). Our findings highlight the vulnerability of longleaf pine across life stages, which suggests optimal fire management strategies for controlling longleaf pine density, and—more broadly—emphasize the importance of fire in mediating species interactions.

Determining the Optimal Density of Phoebe bournei Plantations Based on Dynamic Programming under Close-to-Nature Management Measures

Close-to-nature management (CTNM) is the most promising option for plantation silviculture and has received widespread attention in recent years. Stand density is a key variable in CTNM, as it directly influences growth and yield. Research for the optimal density that maximizes the total harvest has been ongoing. In this paper, a dynamic programming model was applied to the CTNM of Phoebe bournei plantations for the first time to solve the problem of stand density and target tree density control. This paper took Phoebe bournei plantations in Jindong Forest Farm of Hunan Province as the research object. Based on the data of seven consecutive years from 2015 to 2021, Richard’s growth equation was used to fit the height growth equation and basal area growth equation of Phoebe bournei. Stand growth was divided into five development stages according to the forest growth process and characteristics. Stand density and basal area were selected as two-dimensional state variables, and the maximum total harvest in the entire stand growth process was used as the objective function to establish a dynamic programming model. The optimal stand density and target tree density at each growth stage of the stand under three different site conditions were determined. According to the results obtained, the objective forest shape was designed for the stand under three types of site conditions, which can provide a theoretical basis for the CTNM of Phoebe bournei plantations to make the stand achieve the maximum harvest.

Stand Composition, Tree-Related Microhabitats and Birds—A Network of Relationships in a Managed Forest

Forest ecosystems contain many tree-related microhabitats (TreMs), which are used by various groups of organisms. Birds use TreMs for shelter, foraging and breeding. The abundance and variability of TreMs is related to tree stand composition and age. Over the last few centuries there has been a drastic decline in the structural and biological diversity of temperate forests over large areas of the Northern Hemisphere. These changes have reduced the diversity and quantity of TreMs. In this study we showed the relationships between stand composition, the abundance of TreMs, and the species richness of birds in a managed forest. We focused on TreMs that are important to birds: woodpecker breeding cavities, rot holes, dead branches, broken treetops, and perennial polypores. Our study was performed in a managed lowland temperate forest. In 94 plots (10 ha each) we made bird surveys and inventoried the stand composition and TreMs. Our results show that the tree stand composition of a managed forest affects the abundance of TreMs. The share of deciduous trees in the stand favors the occurrence of such TreMs as dead branches, rot holes and perennial polypores. The overall richness of bird species and the species richness of primary cavity nesters depended on the total basal area of oak, hornbeam and birch, whereas the species richness of secondary cavity nesters increased with the total basal area of birch and oak.

Certification of açaí agroforestry increases the conservation potential of the Amazonian tree flora

The harvesting of açaí berries (palm fruits from the genus Euterpe) in Amazonia has increased over the last 20 years due to a high local and global market demand and triggered by their widely acclaimed health benefits as a ‘superfood’. Although such increase represents a financial boom for local communities, unregulated extraction in Amazonia risks negative environmental effects including biodiversity loss through açai intensification and deforestation. Alternatively, the introduction of certified sustainable agroforestry production programs of açaí has been strategically applied to reduce the exploitation of Amazonian forests. Local açaí producers are required to follow principles of defined sustainable management practices, environmental guidelines, and social behaviors, paying specific attention to fair trade and human rights. In this study we investigate whether sustainable agroforestry and certification effectively promotes biodiversity conservation in Amazonia. To address this question, we conducted a forestry inventory in two hectares of long-term certified açai harvesting areas to gain further knowledge on the plant diversity and forest structure in açaí managed forests and to understand the contribution of certification towards sustainable forest management. On average, we found that certified managed forests harbor 50% more tree species than non-certified açaí groves. Trees in certified areas also have significantly higher mean basal area, meaning larger and hence older individuals are more likely to be protected. Certified harvesting sites also harbor dense populations of threatened species as classified by the International Union for Conservation of Nature (e.g. Virola surinamensis, classified as ‘endangered’). Besides increasing the knowledge of plant diversity in açaí managed areas, we present baseline information for monitoring the impact of harvesting activities in natural ecosystems in Amazonia.

Precision and accuracy of sampling methods in thinned Pinus taeda L. stands

Different sampling methods can be used in forest surveys. It is important to know the precision and accuracy of these sampling methods, and which one is the most appropriate in specific conditions of the forest population. The aim of this study was to compare estimates of a forest inventory performed by different sampling methods with forest census results. The sampling methods evaluated were the fixed-area method and the variable-area methods of Bitterlich, Prodan, and Strand. The data were obtained in a 15-year-old thinned stand of Pinus taeda L., located in the municipality of Teixeira Soares, southern Brazil, with a total area of 12.80 ha. Initially, the forest census was carried out, and subsequently, the sample units for each sampling method were distributed in the stand, with a common starting point. The variables used to compare the sample results with the census means were quadratic diameter, number of trees, basal area, and volume, per hectare. Precision and accuracy were evaluated by sampling error and whether the confidence intervals covered the population means, respectively. The fixed-area and Bitterlich methods stood out in precision for all variables analysed. The fixed-area, Bitterlich and Strand methods with proportion to height provided more accurate estimates. The Prodan method provided inaccurate and imprecise estimates for the variables under analysis, except for the quadratic diameter.

Importance Of Small Diameter Woody Plants And Treelet Species In Tropical Wet Evergreen Forest Of Southern Western Ghats, India

Tropical forests have long been accepted for their productivity and ecosystem services on account of their high diversity and stand structural attributes. In spite of their significance, tropical forests, and especially those of Asia, remain understudied. Until recently, most forest inventories in Asia have concentrated on trees 10 cm in diameter. Floristic composition, plant species diversity, above-ground biomass, basal area, and diversity were investigated across different life forms and two-diameter classes in a large-scale 10-ha plot, in the undisturbed tropical seasonal rain forest of Southern Western Ghats, Kerala, India. The regeneration pattern of the study area was examined by evaluating fisher's alpha and IVI (Important Value Index) across three layers of vegetation (seedling, sapling, and tree). Within the plot, we recorded 25,390 woody plant species ≥1 cm dbh from 45 families, 91 genera, and 106 species. Plant density was 2539 woody individuals per hectare, with a basal area of 47.72 m2/ha and above-ground biomass of 421.77 Mg/ha. By basal area, density, and frequency, the Rubiaceae, Sapotaceae, and Malvaceae families were the most important. Small-diameter trees (1 cm ≤ dbh ≤10 cm) were found to be 78 percent of the total tree population, 20.2 percent of the basal area, and 1.4 percent of the aboveground biomass. They also possessed 6 percent more diversity at the family level, 10% more diversity at the genus level, and 12% more diversity at the species level than woody individuals under 10 cm dbh. Woody individuals of treelets life form and small-diameter classes were much more diverse and dense than the other groups, indicating that results based only on larger canopy trees and larger diameter class maybe not be an appropriate representation of the diversity status of a particular tropical forest type. The lower density of individuals in the initial girth class indicates the vulnerability of the forest system to anthropogenic, natural disturbance and a changing climate. Reduce the minimum diameter limit down to 1 cm, in contrast to 10 cm limit used in most of the evergreen forest inventories, revealed a high density and diversity in the lower stories.

Silviculture can facilitate repeat prescribed burn programs with long-term strategies

A significant expansion of prescribed fire activity will be necessary to mitigate growing wildfire hazard in California forests. Forest managers can facilitate this expansion by promoting forest structures that allow for more effective implementation of prescribed fire, for both initial-entry and repeat burns. We analyzed changes in surface fuel during a series of three burns in replicated mixed-conifer stands following a period of over 100 years of fire suppression and exclusion. Total fuel load, proportion of pine present, canopy cover and basal area of live trees were relevant forest-structure components that influenced plot-scale fuel consumption. The study highlighted the importance of pre-fire fuel load and the relative proportion of pine in the overstory, which both led to greater amounts of fuel consumption. The initial-entry burn dramatically reduced all fuel categories (fine fuel, coarse wood and duff). Following each burn, fuel recovered until the next burn reduced loads enough to maintain low fuel levels. We apply the results to provide an example of how to determine the timing of prescribed fires.

Effect of Land Cover Differences on Soil Infiltration at UB Forest, Karangploso Malang

Changes in land cover of forest provide different soil organic matter which affects soil infiltration through soil porosity. The purpose of this study was to determine the effect of differences in land cover on soil infiltration at UB Forest of Karangploso Malang. The study area was divided into six plots, namely protected area plots, mahogany production forests, pine production forests intercropped with coffee plants that have three different canopy densities (tenuous, sufficient and tight) and pine production forests intercropped with seasonal crops. Field observations were carried out to analyze the characteristics of vegetation with a sample plot measuring 20x20 m. The parameters observed were canopy density, basal area, plant density, litter and understorey. The taking of soil samples was done by making minipit which was repeated four times; the parameters observed were organic matter, texture, bulk density, particle density and soil porosity. Infiltration measurements were carried out with two methods i.e. single ring infiltrometer and rainfall simulator, each of which was repeated three times. Observation data were subjected to Analysis of Variance (ANOVA) and followed by with LSD test with a significant level of 5%. The results showed that differences in land cover can affect soil infiltration (F-count > F-table 3.33). The effect of land cover on infiltration occurs through litter which is a source of organic material which will then affect the physical properties of the soil, namely soil porosity. Soil porosity is a very influential factor in soil infiltration. The highest soil infiltration reta of 131.33 cm hour-1 was found in protected areas. Meanwhile, the lowest infiltration rate of 12 cm hour-1 was found in pine production forest plots intercropped with annual crops.