Response of soil bacterial community to biochar application in a boreal pine forest

Boreal forests commonly suff er from nitrogen defi ciency due to low rate of nitrogen mineralization.Biochar may promote soil organic matter decomposition and accelerate nitrogen mineralization.In this study,Illumina NovaSeq sequencing combined with functional annotation of prokaryotic taxa(FAPROTAX)analysis was used to investigate the eff ect of biochar pyrolysis temperatures,the amount of applied biochar,and the period since the biochar application(2-and 3-year)on soil bacterial communities.The results show that biochar pyrolysis temperatures(500℃ and 650℃)and the amount of applied biochar(0.5 kg m^(−2)and 1.0 kg m^(−2))did not change soil properties.Nevertheless,the interaction of biochar pyrolysis temperature and the amount had signifi cant eff ects on bacterial species richness and evenness(P<0.05).The application of biochar produced at 500℃ had a lower abundance of Actinobacteria and Verrucomicrobia,while that produced at 650℃ had a higher abundance of Conexibacter and Phenylobacterium.When biochar produced at 650℃ was applied,applying 0.5 kg m^(−2)had a higher abundance of Cyanobacteria,Conexibacter,and Phenylobacterium than that of 1.0 kg m^(−2)(P<0.05).Functionally,the abundance of the aromatic compound degradation group increased with the extension of application time and increase of pyrolysis temperature.The time since application played an important role in the formation of soil bacterial communities and their functional structure.Long-term studies are necessary to understand the consequence of biochar on bacterial communities in boreal forests.

Dynamics of mediterranean pine forests reforested after fires

Forest fires are frequent under a Mediterranean climate and have shaped the landscape of the region but are currently altered by human action and climate change.Fires have historically conditioned the presence of pine forests,depending on severity and forest regeneration.Regeneration of Mediterranean pine forests is not always successful,and a transition to shrublands or stands of resprouting species can occur,even after reforestation.This study analyses vegetation changes in two Mediterranean pine forests after severe fires and both reforested.The pines had difficulty to regenerate,even despite post-fire reforestation.The problem is the difficulty of young seedlings to survive,possibly due to increased summer drought.Problems are greater in pine species at the limit of their ecological tolerance:Pinus pinea had a much better recovery success while P.sylvestris and P.nigra virtually disappeared.Pinus pinaster had intermediate results but recovery was generally poor.A transition has taken place in many burnt areas to scrubland or to thickets of the resprouting Quercus rotundifolia,although it is not possible to know whether they will evolve into forests or remain in a sub climatic state.Resprouting species may increase fire severity but facilitates post-fire colonisation.Post-fire recovery difficulties are closely linked to issues of natural regeneration.Fire could initiate the disappearance of pine forests,but even in the absence of fire they may disappear in the long-term due to the lack of regeneration.Action is needed to increase the resilience of these forests,ensuring natural regeneration,and incorporating resprouting species in the understorey.

Factors controlling N_2O and CH_4 fluxes in mixed broad-leaved/Korean pine forest of Changbai Mountain, China

Using the closed chamber technique, the in situ measurements of N2O and CH4 fluxes was conducted in a broad-leaved Korean pine mixed forest ecosystem in Changbai Mountain, China. from June 1994 to october 1995. The relationships between fluxes (N2O and CH4) and some major environmental factors (temperature, soil water content and soil availabIe nitrogen) were studied. A significant positive correlation between Nzo emission and air/soil temperature was observed, but no significant correIation was found between N2O emission and soil water content (SWC). This result showed that temperature was an important controlling factor of N2O flux. There was a significant correlation between CH4 uptake and SWC, but no significant correlation was found between CH4 uptake and temperature. This suggested SWC was an important factor controlling CH4 uptake. The very significant negative correlation between logarithmic N2O flux and soil nitrate concentration, significant negative correlation between CH4 flux and soil ammonium content were also found.

The influence of selective cutting of mixed Korean pine(Pinus koraiensis Sieb.et Zucc.) and broad-leaf forest on rare species distribution patterns and spatial correlation in Northeast China

This study aimed to demonstrate change in spatial correlation between Korean pine （Pinus koraiensis Sieb. et Zucc.） and three rare species, and change in spatial distribution of four species in response to a range of selective cutting intensities. We sampled three plots of mixed Korean pine and broad-leaf forest in Lushuihe Forestry Bureau of Jilin province, China. Plot 1, a control, was unlogged Korean pine broad-leaf forest. In plots 2 and 3, Korean pine was selectively cut at 15 and 30 % intensity, respectively, in the 1970s. Other species were rarely cut. We used point-pattern analysis to research the spatial distributions of four tree species and quantify spatial correlations between Korean pine and the other three species, Amur linden （Tilia amurensis Rupr.）, Manchurian ash （Fraxinus mandshurica Rupr.）, and Mongolian oak （Quercus mongolica Fisch.） in all three plots. The results of the study show that selective cutting at 15 % intensity did not significantly change either the species spatial patterns or the spatial correlation between Korean pine and broadleaf species. Selective cutting at 30 % intensity slightly affected the growth of Korean pine and valuable species in forest communities, and the effect was considered nondestructive and recoverable.

Conserving and restoring the Caicos pine forests: The first decade

The severe and rapid attack on the Caicos pine Pinus caribaea var. bahamensis(Pinaceae) by the nonnative invasive pine tortoise scale, Toumeyella parvicornis, has resulted in the death of most of the trees in the Turks and Caicos Islands(TCI) in just over a decade. Local and international conservation efforts have enabled the necessary multi-disciplinary research, data gathering, and monitoring to develop and implement a restoration strategy for this endemic tree from the Bahaman archipelago. The native plant nursery established on North Caicos and horticultural expertise acquired throughout the years were crucial to the successful rescue of Caicos pine saplings from the wild populations and cultivation of new saplings grown from locally sourced seeds. These saplings have been used to establish six Restoration Trial Plots on Pine Cay and a seed orchard on North Caicos in TCI. Core Conservation Areas(CCAs) for the Caicos pine forests have been identified and mapped. To date, forest within the Pine Cay CCA has been supplemented by planting more than 450 pine trees, which have survived at a high(>80%)rate.

Stone Pine Forests in Siberia

Stone pine forests in Siberia are unique for their origin, area dynamics, comprehensive productivity, and biospherical role. They are mainly mature forests for the most regions. The regeneration has two main tasks. (1) to organize the rational and ecological felling for the Siberian stone pine trees, (2) to increase young growth. In the past, the main aboof the forest management was wood production. The basic elements were mainly technical exploitability and felling ages, traditional cleaning cutting, and "continuous" artificial regeneration, which are not suitable for the Siberian Stone pine for-ests. New practices of the forest management and new theoretical principles have been developed by our Institute: including comprchenshe evaluation, selection and growth, and creating new felling technology. Qualitative evaluations of every Stand and every tree in the Siberian stone pine forests should be made.

Site Quality Evaluation for Mixed, Uneven-aged, Natural Forest Dominatedby Korean Pine in Northeast China

Six site types of Korean pine(Pinus koraiensis) forest, Mongolian oak type, Yezo spruce type, Korean spruce type, Amur linden type, Ribbed birch type and Manchurian ash type, are easily found on the south slope of Xiaoxing’an Mountains. The analysis results of H-A and H-Dbh relationships by site type showed that height growth of Korean pine dominant or codominant stems in natural stands is not directly related to its age but is directly related to its diameter, which closely accords with the Chapman-Richards equation(Relativity coefficients more than 0:8668). A method for evaluating site quality using height and diameter of dominant or codominant tree independent of tree age is examined. There are signifi-cantly differences in site quality of Korcan pine among six site types above. The site index was highest on Manchurian ash type, and lowest on Mongolian oak type. Differences of site index with a reference dbh of 40 cm between highest and lowest sites can reach 11 m in maximum., 7 m in average, respectively. Other rationales of the H-D method were discussed.

Response of ground beetles(Coleoptera:Carabidae)to forest gaps formed by a typhoon in a red pine forest at Gwangneung Forest,Republic of Korea

In Korea, damaging typhoons related to climate change have increased steadily since the 1990s. Red pine （Pinus densiflora） forests in Gwangneung Forest were greatly disturbed by typhoon Kompasu in 2010. A survey was carried out to clarify differences in ground beetle （Coleoptera： Carabidae） communities between forest gaps and undamaged forests. Ground beetles were sampled using pitfall traps from early May to late October 2011. Vegetation changes, litter layer, organic matter layer, and soil conditions were also measured. A total of 1035 ground beetles of 32 species were collected. Contrary to our expectation, species richness, abundance, and community structure of the ground beetles in forest gaps were similar to those in undamaged forests. Species richness and abundance of habitat type were also similar. However, species diversity and estimated species richness in forest gaps were significantly higher than in undamaged forests. These findings suggest that forest gaps formed by a typhoon did not lead to great change in ground beetle communities.

A preliminary study on the characteristics of fogwater in the masson pine forest in Chongqing, China

The masson pine (Pinns massoniana Lamb.) forest of 2000 ha situated on Nanshan, the south bank of the Yangtze River near Chongqing, China. From 1982, some trees began to die. Since then, half of the trees have died and the whole forest is in danger. Prom November 1986 to January 1987, a study dealt with the characteristics of fogwater in that area was carried out, in order to explain the relationship between acid fog and masson pine decline. The results of our study showed that the acid fog might be responsible in part for the decline of the masson pine forest.

Dynamics of nitrogen nutrition of coexisting dominant trees in mixed broad-leaved/Korean pine forest

Chemical analysis of ammonium, nitrate and total nitrogen in tree leaves and roots and anin-vivo bioassay for nitrate reductase activity (NRA) were used to monitor the seasonal variations in nitrogen assimilation among four coexisting dominant tree species, includingPinus koraiensis, Tilia amurensis, Fraxinus mandshurica andAcer mono, in a virgin mixed broad-leaved/Korean pine (Pinus koraiensis) forest. The soil study included individual horizons of L+F (0–5 cm), Ah (5–11 cm) and Aw (11–25 cm). All four species had nitrate and ammonium in their roots and leaves, and also NRA in leaves. This indicated that these coexisting species were adapted to ammonium + nitrate nutrition. A negative correlation existed between nitrate use and ammonium use. Ammonium concentration was higher than that of nitrate in tree leaves and roots, and also in soils, which indicated climax woody species had a relative preference for ammonium nutrition. There was a positive relationship between tree nitrogen nutrition use and soil nitrogen nutrient supply. Utilization of ammonium and nitrate as well as the seasonal patterns differed significantly between the species. Peaks of ammonium, nitrate, NRA and total nitrogen in one species were therefore not necessarily synchronous with peaks in other species, and which indicated a species-specific seasonal use of nitrogen. The species-specific temporal differentiation in nitrogen use might reduce the competition between co-existing species and may be an important mechanism promoting stability of virgin mixed broad-leaved//Korean pine forest.

A succession and silviculture model for the broad-leaved Korean pine forests of Changbai Mountain Area

A succession and silviculture model (ZELIG.CBA) for broad-leaved Korean pine forest of Changbai Moutain Area was developed based on the framework of ZELIG model and characteristics of Broad-leaved Korean pine forests of Changbai area. ZELIG.CBA model consists four sub-models: growth model simulating annual increment of individual tree in forest, regeneration model simulating annual establishment of different tree species, mortality model simulating annual agerelated and stress-related morality; and silviculture model simulating the forest response to different silviculture scenario. The validation of the ZELIG.CBA showed that the accuracy of the model for the forest growth was more than 95%. The succession from clear cutting site simulating showed that the ZELIG.CBA model was stable for long term simulation. And selective cutting experiment showed that the optimal scenario for broad-leaved Korean pine forests was removal volume 30% combining with 30a rotation.

NITROGEN NUTRIENT MECHANISM IN SECONDARY SUCCESSION PROCESS OF THE MIXED BROAD-LEAVED/ KOREAN PINE (PINUS KORAIENSIS) FOREST

Chemical and biochemical analysis methods were used to monitor the vedations of nitrogen nutrient among the dominance trees species in secondary succession process of the mixed broad - leaved/Korean pine forest on Changbai Mountains, Northeast China. Amounts of total nitrogen, anunonium and NRA in soils of virgin broad-leaved/Korean pine forest which is in climax were higher than those of secondary birch forests those are in succession Stage. The amount of nitrate was in the other hand. In climax, dominance trees species are tolerant mesophytic trees such as Pinus Koraiensis, Tilia amurensis, Acer mono and also Fraxinus mandshurica, they are all ammonium + nitrate adapted species, but they show a preference for the anunonium rather than those of the pioneer trees species in secondary birch forest, such as Populus davidiava and Betula platyphylla. Because they have more ammonium in their leaves and roots, especially Pinus koraiensis. Populus davidvana and Betula plaaphlla are intolerant trees, amounts of nitrate and total nitrogen is higher in their leaves and roots and also NRA in their leaves, so they preference for the nitrate rather than the others.In secondary birch forest, the regeneration trees species adapt their nitroggn nutrient to the variation of nitrogen nutrient situation in soil, finally they could survival well and the secondary birch forest would succession to climax. In climax, dominance trees species adapt their Nitrogen nutrient to the situation in soil and there are not strong competition in nitrogen nutrient among them, so they can coexist well and keep the climax as stable vegetation.

Effects of Logging Intensity on Structure and Composition of a Broadleaf-Korean Pine Mixed Forest on Changbai Mountains,Northeast China

In order to identify a harvesting model which is beneficial for broadleaf-Korean pine mixed forest(BKF) sustainability, we investigated four types of harvested stands which have been logged with intensities of 0(T0, control), 15%(T1, low intensity), 35%(T2, moderate intensity), and 100%(T3, clear-cutting), and examined the impacts of logging intensity on composition and structure of these stands. Results showed that there were no significant differences between T0 and T1 for all structural characteristics, except for density of seeding and large trees. The mean diameter at breast height(DBH, 1.3 m above the ground), stem density and basal area of large trees in T2 were significantly lower than in T0, while the density of seedlings and saplings were significantly higher in T2 than in T0. Structural characteristics in T3 were entirely different from T0. Dominant tree species in primary BKF comprised 93%, 85%, 45% and 10% of the total basal area in T0, T1, T2 and T3, respectively. Three community similarity indices, the Jaccard′s similarity coefficient(CJ); the Morisita-Horn index(CMH); and the Bray-Curtis index(CN), were the highest for T0 and T1, followed by T0 and T2, and T0 and T3, in generally. These results suggest that effects of harvesting on forest composition and structure are related to logging intensities. Low intensity harvesting is conductive to preserving forest structure and composition, allowing it to recover in a short time period. The regime characterized by low logging intensity and short rotations appears to be a sustainable harvesting method for BKF on the Changbai Mountains.

SECONDARY SUCCESSION OF NATURAL KOREAN PINE FORESTS

The secondary succession of natural Korean pine(Pinus koraiensis ) forests in Fenglin Nature Reserv, located at northem section of south slope of Xiaoxing’an Mountains, Heilongjiang, wasinvestigated . The currat forest types are ropreseded by broadleaved mixed forests dominated bywhite birch (Betula platyphylla ) and broadleaved-coniferous mixed forest dominated by larch(Larix gmelini). The secondary forests developed after a fire in 1931. Studied results showed that conderousspecies and hardwod species could replace the pioneer species together and the secondary forestscould reach the climax community without passing the hard broadleaved Stage. As the pioneer speciesfor replacing Korean pine, the oak forest was faster, the following was white birch forest, and the lastwas lawh-white birch fotal. For replacing spruce, the white birch forest and larch-white birch foresthad best results and the following was poplar forest and oak forest. White birch forest and larch-whitebirch forest had best result in replacing fir forest.

SMALL-DIAMETER KOREAN PINES AND THEIR ROLES INNATURAL KOREAN PINE FOREST

Korean pine population strueture in natural Korean pine forest was studied through massive field investigation and indoor analvsis. Small-diameter Korean pines origination, growth charaeter and their roles in stand were discussed from the view of population origination and tree growth. The results show that small-diameter Korean pines origination and growth havc close relations to the overstory canopy structure dynamics and play an important role in the maintenance and development of Korean pine forest. The process from small-diameter trees to dominant canopy is a selfmaintenance phase, with diffieulty, in Korean pine population. To complete this phase, it not only demands some morphological characters and physiological conditions, but severe forest strueture conditions as well. The time for complating this phase needs separation from overstory Korean pines and converge with overstory broad-leaf trees. In vertical space, it needs to fell overstory canopy or reduce the layers of overstory canopy, and in horizontal space it should be separated from Korean pines but accompanied by broad-leaf trees.

Optimum stand density of Chinese pine forests in Taihang limestone mountains, Shanxi Province

Data analysis was made for 54 stands of Chinese pine forests for soil and water conservation and timber. The regression equations were drawn up on forest density and different rafter timber and bush coverage.Based on those equations, the number of rafter timber trees, storage, number of non-raffer timber trees, stand volume and the output value were calculated for six different forest densities ranged from 1250 to 6600 trees/hm2.According to the economic and ecological criteria, the optimum density for Chinese pine forests was determined as 1 650 trees/hm2.

MORE ATTENTION TO PROTECTION AND RESEARCH ON OLD-GROWTH KOREAN PINE (PINUS KORAIENSIS) FORESTS

This paper reviews the researches on old-growth korean pine (Pinus koraoensis) forest in Northeast China. The ecological characteristies of the forest were summarized. According to the researeh results, the importance of studying and reserving on the old-growth forest was addressed, which were the indispensable research laboratory and classroom for forest managers. The conelusions indicate that the future of Korean pine forest management should be based on the research results of oldgrowth forests.

The relationship of structure and regeneration of broad-leaved Korean pine forest on the north slope of Mt.Changbai

Studies were carried out on the spalial patterns of dominant species and gaps, and the influence of which on the regeneration in the broad-leaved Korean pine forest on the north slope of Mt. Changbai. The result showed that many deciduous tree species have high growth rates and become more competitive due to the more mild and humid climate at Mt.Changbai. No obvious aggregated distribution pattern was showed. In this forest small gaps are most frequent, with even distribution, which may be beneficial to survival and growth of Pinus koraiensis saplings.

Growth models and site index table of natural Korean pine forests

According to the growth characteristics of natural Korean pine (Pinus Koraiensis) forests, 6 equations such as Chapman-Richards equation, Logistic equation, Power equation, and so on were selected to ftt for the growth modeIs for Korean pine forest. The growth models were developed based on 208 random trees and 24o dominant trees. Results show that the Chapman-Richards equation is the best model for estimating tree height by age and DBH, while the Parabola equation is fittest for predicting DBH by age or estimating age from DBH. The site index table of Korean pine forest was compiled by using the proportional method with the Chapman-Richards equation as the guide curve and vaIidated by accuracy test.