Cedar Stands Research Articles

Contrasting survival strategies for seedlings of two northern conifer species to extreme droughts and floods.

Lowland northern white-cedar (Thuja occidentalis) forests are increasingly exposed to extreme droughts and floods that cause tree mortality. However, it is not clear the extent to which these events may differentially affect regeneration of cedar and its increasingly common associate, balsam fir (Abies balsamea). To test this, we measured how seedlings of cedar and fir were able to avoid, resist, and recover from experimental drought and flood treatments of different lengths (8-66days). Overall, we found that cedar exhibited a strategy of stress resistance and growth recovery (resilience) from moderate drought and flood stress. Fir, on the other hand, appears to be adapted to avoid drought and flood stress and exhibited overall lower growth resilience. In drought treatments, we found evidence of different stomatal behaviors. Cedar used available water quickly and therefore experienced more drought stress than fir but cedar was able to survive at water potentials > 3MPa below key hydraulic thresholds. On the other hand, fir employed a more conservative water use strategy and therefore avoided extremely low water potential. In response to flood treatments, cedar survival was higher and only reached 50% if exposed to 23.1days of flooding in contrast to only 7.4days to reach 50% mortality for fir. In both droughts and floods, many stressed cedar were able to maintain partially brown canopies and often survived the stress, albeit with reduced growth, suggesting a strategy of resistance and resilience. In contrast, fir that experienced drought or flood stress had a threshold-type responses and they either had full live canopies with little effect on growth or they died suggesting reliance on a strategy of drought avoidance. Combined with increasingly variable precipitation regimes, seasonal flooding, and complex microtopography that can provide safe sites in these forests, these results inform conservation and management of lowland cedar stands.

An Eco-Dendrometric Study of Atlas Cedar (Cedrus Altantica Manetti) from Theniet-El-Had National Park (North West of Algeria)

Purpose: This work contributes to the study of the growth pattern of Atlas Cedar (characterized by dendrometric variables) relevant to the stands from Pepinière canton in relation to site factors (ecological and pedology descriptors). Theoretical framework: A forest ecosystem is a complex set of external factors that have a positive or negative effect on tree growth. Species ecology is a key point in understanding their behavior in relation to environmental fluctuations. Method: Forty-six temporary plots were set up to collect ecological, pedological, and dendrometric data, allowing for a characterization of the growth pattern of Atlas Cedar stands. Results and conclusion: The study highlights the presence of an unmanaged irregular forest. Despite being located in an environment conducive to its growth, this forest is subject to degrading anthropogenic activity. Analysis of variance at a significance level of 95% shows that altitude and limestone content are the main site factors influencing Atlas Cedar growth. Research implications: knowledge of the growth rate of this species allows better silvicultural operations, and application of more adequate management plans for this endemic protected species. Originality/value: This study constitutes a reliable scientific tool for forest managers, particularly in national reforestation plans, which are doomed to failure due to a lack of knowledge of the behavior of the species used.

Reduction in the ratio of stemflow to rainfall during heavy rain in two Japanese cedar stands and the influence on rainfall partitioning

Stemflow (SF) and gross rainfall (GR) were measured in two Japanese cedar stands with stand densities (SDs) of 5700 trees/ha and 9700 trees/ha. SF water was collected from four trees in each stand, and SF was derived by dividing the volume by the canopy area of the trees. In previous studies the highest SD for SF measurements in Japanese cedar and cypress was 2500 trees/ha with SF/GR of 23.3%. In this study SF/GR in the 5700-trees/ha and the 9700-trees/ha stands were 34.0% and 53.3%, respectively. Literature data together with the results of this study showed linear relationship between SF/GR and SD. In both cedar stands SF increased linearly with increasing GR on a rain event basis, however, a bending point in linearity that is defined as a threshold appeared for GR > 100 mm in the 9700-trees/ha stand, over which the slopes of the regression line became gentler. The 10-minute analyses also revealed the threshold and gentler slope of the regression line during intense rainfall. The threshold values were not constant but ranged from 4 to 8 mm/10 min. One of the causes of the threshold is splash droplets generated by raindrops hitting canopy and trunks, and another is SF water that breaks away from branches and stems. Both of them become throughfall (TF) and reduce rainwater allocated to SF during intense rainfall. The past measurements on TF and canopy interception (CI) conducted at the same site as this study showed the threshold, over which CI/GR increased. The existence of the threshold in CI/GR means some rainwater that was not allocated to SF but became TF evaporated as splashes before reaching the forest floor. Reduction in SF/GR influences rainfall partitioning in the stands.

Reduction in the Ratio of Stemflow to Rainfall During Heavy Rain in Two Japanese Cedar Stands and the Influence on Rainfall Partitioning

Reduction in the Ratio of Stemflow to Rainfall During Heavy Rain in Two Japanese Cedar Stands and the Influence on Rainfall Partitioning

Late phase radiocesium dynamics in Fukushima forests post deposition

The long term dynamics of radiocesium in typical forest ecosystems was studied in the radioactive contaminated areas in Fukushima Prefecture. Six observations sites located in Yamakiya Village (Kawamata Town; since 2014), Tsushima Village (Namie Town, since 2015), and Tomioka Town (since 2017) were monitored. The forests consisted of artificial plantations of Japanese cedar (Cryptomeria japonica) at Yamakiya Village, Tsushima Village, and Tomioka Town. Tsushima Village also had a natural mixed forest dominated by Japanese red pine (Pinus densiflora), and Tomioka Town had a young and a mature artificial plantation of Japanese cypress (Chamaecyparis obtuse). Concentrations of 137Cs were monitored in the samples collected from the main aboveground biomass compartments, fresh litterfall, forest litter, and soil. Concentrations of exchangeable forms of 137Cs and stable K were measured in soil samples. During the observation period, the litter radiocesium inventories at all sites decreased significantly to approximately 1% or less of the total ground deposition. Approximately 80% of the total radiocesium inventory is localized in the upper 5-cm layer of soil and there is little downward migration of radiocesium. At the sites with the longest monitoring series (Yamakiya and Tsushima), the radiocesium expectation depths and expectation mass depths were relatively constant at 2–3 cm and 5–6 kg m−2, respectively. Aboveground biomass compartments showed similar decreasing trends in radiocesium aggregated transfer factors, Tag, in the compartments that were exposed to atmospheric fallout in March 2011 (old foliage, small branches, and outer bark). The mean Tag in cedar stand compartments currently are in the range of 10−3-10−2 m2 kg−1 dw. However, the mean Tag and their dynamic trend significantly differed in the wood compartments of the cedar stands, which may indicate root uptake differences of orders of magnitude between observation sites. The difference in radiocesium concentration in wood between the sites becomes less pronounced when normalized by the ratio of exchangeable 137Cs/K in the soils.

Role of Egg Parasitoids in Controlling the Pine Processionary Moth in the Cedar Forests of Chréa National Park (Algeria)

The sustainable protection of cedar stands in Chréa National Park can only be accomplished through the stability of the ecosystem. Outbreaks of Thaumetopoea pityocampa are a major threat and are largely attributed to the high population fecundity, changes in the diversity of natural enemies and global interactions within the ecosystem. Egg parasitoids (Hymenoptera) are essential in the biological control of T. pityocampa. To assess the impact of the parasitoids on the populations of the pine processionary moth, egg masses from cedar plantations were collected, reared in a laboratory and checked regularly for the emergence of the egg parasitoids: Trichogramma embryophagum, Baryscapus servadeii and Ooencyrtus pityocampa. Observations showed an inter-annual variation in the abundance of the three parasitoids as a result of the variation in the population density of the processionary moth, and on the underlying effect of temperature. Parasitoids had variable parasitism rates, with yearly averages ranging from 3.86% to 51.14%, dependent on the spatiotemporal distribution of the host populations. The aggregate effect of multiple parasitoid species could optimize control of T. pityocampa in cedar stands.

IMPACT OF NATURAL ENEMIES ON LARVAE OF THAUMETOPOEA BONJEANI (LEPIDOPTERA NOTODONTIDAE) IN ASSOCIATION WITH THAUMETOPOEA PITYOCAMPA IN NORTHERN ALGERIA

The cedar processionary moth, Thaumetopoea bonjeani (Lepidoptera: Notodontidae), is a serious pest of the Atlas cedar Cedrus atlantica in north-western Africa and it is involved in the decline of this endangered tree species. Natural enemies of the cedar processionary moth are poorly known, especially for parasitoids, predators and pathogens of the larval-pupal life stages. Mature larvae were collected and examined in 2014 and 2015 in natural stands of Atlas cedar in the Djurdjura (northern Algeria), in occurrence with pine processionary moth Thaumetopoea pityocampa. The overall mortality rate of larvae of Thaumetopoea bonjeani ranged from 26.4% to 31.1%, with generalist predators and parasitoids being more effective than pathogens. Four primary parasitoid species were recorded, of which four tachinid flies and one braconid wasp, as well as four predatory beetles and one fungus. The most important species were the carabid Calosoma sycophanta and the tachinid Compsilura concinnata. The cooccurrence of T. bonjeani and T. pityocampa may offer to generalist natural enemies an extended period of availa- bility of similar preys, as the two processionary moths have different life cycles. The sharing of natural enemies between the two species of Thaumetopoea can mitigate the outbreaks of both species.

Timber harvesting on fragile ground and impacts of uncertainties in the operational costs

ABSTRACT Forested wetlands with high water tables are sensitive to disruption from harvesting yet support commercially desired tree species like northern white-cedar. Winter harvest was conducted in Maine, USA, to compare operational costs and productivity of cut-to-length harvesting in cedar (fragile soil) and non-cedar stands (mixedwood, sturdy soil), evaluate uncertainties in harvesting costs and influential factors, and forecast time for post-harvest recovery to pre-harvest volumes. Operational costs were calculated using detailed time and motion studies. Operational costs for the cedar stands were higher than non-cedar. Regression models were developed for harvesters, forwarders, and self-loading trucks; number of logs per cycle was a common factor. Sensitivity analysis showed the dependence of operational costs on labor and fuel costs. Forest Vegetation Simulator projections were used to assess harvest sustainability and suggested the time required to regrow harvested merchantable volume is comparable to cutting cycles recommended for similar treatments in the region. Predicted growth rates exceed those reported regionally on similar sites, suggesting additional study of post-harvest response is warranted. Results highlight site constraints on both operational and stand productivity in lowlands and will be useful for timber harvesting decision-making and forest management planning if combined with assessment of residual stand growth response.

Microsite requirements for successful regeneration in lowland northern white-cedar (Thuja occidentalis L.) forests

Throughout much of its range, northern white-cedar (Thuja occidentalis L., hereafter cedar) has experienced a bottleneck in recruitment: cedar seedlings are often abundant in these stands, particularly in lowland settings, yet cedar sapling densities are quite low, leading to concerns that cedar canopy trees are not being replaced. Several barriers to cedar recruitment have been suggested; however, findings from previous studies have been inconsistent with regard to limiting factors. Our objective was to characterize the microsite conditions associated with the establishment of cedar seedlings and saplings. We achieved this objective by mapping the location of seedlings, saplings, and overstory trees in 15 lowland cedar stands at five sites in Maine, USA, and examining the fine-scale site conditions (microtopographic features, canopy openness) in which cedar seedlings and saplings occurred. In particular, we recorded the occurrence of seedlings and saplings on microtopographic mounds, pits (small depressions), and flats (transitional features between mounds and pits). Substrate moisture content in these features decreased in the order pits > flats > mounds. Contingency-table results demonstrated that live cedar seedlings, and to a slightly lesser extent saplings, were found more often than expected by chance on mounds, and less often on flats and pits. Logistic regressions using status (live vs. dead) as the response variable generally supported these findings: dead seedlings were strongly associated with pits; however, the occurrence of live seedlings and saplings did not differ between flats and mounds. A companion planted-seedling experiment strongly supported these results, showing that after two growing seasons, survival was significantly lower in pits (12%) when compared to flats and mounds, which had similarly high levels of survival (62 and 80% respectively). Logistic regressions also showed live seedlings and saplings to be prevalent under more open canopy conditions (mean 19%, range 6 to 42% openness); though results from a planted-seedling experiment suggested that greater canopy openness (mean 32%, range 13 to 57%) was detrimental to survival. Regressions also showed that browsed seedlings were more likely to be found dead. These findings point to management prescriptions that maintain microtopographic diversity, create moderately open canopy conditions, and protect stands from browsing to promote viable cedar populations in these ecologically and economically important forests.

Implications of ectomycorrhizal inoculation for drought stress tolerance of Atlas cedar (Cedrus atlantica (Endl.) Carrière) seedlings

Background: Ectomycorrhizal inoculation is a promising strategy to minimise the initial transplant shock and increase plant survival and growth during the first years of out-planting in the field. The aim of this research was to investigate the effect of sporal inoculum of three ectomycorrhizal fungi: Cortinarius cedretorum, Amanita vaginata and Inocybe geophylla on tolerance levels of Atlas cedar (Cedrus atlantica (Endl.) Carrière) seedlings subjected to applied drought stress in nursery conditions. Methods: Carpophores, seeds and organic forest soil were collected under pure stands of Atlas cedar. After fifteen months of growth, seedlings were subjected to drought stress by withholding water for thirty days; we assessed morphological and physiological variables of all seedling batches (inoculated and uninoculated, controlled and stressed seedlings) Results: All roots of inoculated stressed seedlings were mycorrhizal. The mycorrhization rates were 67%, 64.6% and 53.6% for stressed seedlings inoculated with Cortinarius cedretorum, Amanita vaginata, Inocybe geophylla, respectively. This root mycorrhization was accompanied by a significant improvement in seedling growth, especially height and length of the main root (10.2 cm, 52 cm) reached in stressed seedlings inoculated with Cortinarius cedretorum. There was a significant increase in relative water content, total chlorophyll, carotenoids, soluble sugars and starch, superoxide dismutase and ascorbate peroxydase enzyme activities in inoculated stressed seedlings compared with uninoculated seedlings. Conclusions: Inoculation of Atlas cedar seedlings with spores of ectomycorrhizal fungi remains a very effective alternative for improving growth and the morphological and physiological status of seedlings under drought conditions. Cortinarius cedretorum appears to be consistently advantageous followed by Amanita vaginata and Inocybe geophylla.

Carbon stock estimation by dual-polarized synthetic aperture radar (SAR) and forest inventory data in a Mediterranean forest landscape

Forest ecosystems play a crucial role in mitigating global climate change by forming massive carbon sinks. Their carbon stocks and stock changes need to be quantified for carbon budget balancing and international reporting schemes. However, direct sampling and biomass weighing may not always be possible for quantification studies conducted in large forests. In these cases, indirect methods that use forest inventory information combined with remote sensing data can be beneficial. Synthetic aperture radar (SAR) images offer numerous opportunities to researchers as freely distributed remote sensing data. This study aims to estimate the amount of total carbon stock (TCS) in forested lands of the Kizildag Forest Enterprise. To this end, the actual storage capacities of five carbon pools, i.e. above- and below-ground, deadwood, litter, and soil, were calculated using the indirect method based on ground measurements of 264 forest inventory plots. They were then associated with the backscattered values from Sentinel-1 and ALOS-2 PALSAR-2 data in a Geographical Information System (GIS). Finally, TCS was separately modelled and mapped. The best regression model was developed using the HH polarization of ALOS-2 PALSAR-2 with an adjusted R2 of 0.78 (p < 0.05). According to the model, the estimated TCS was about 2 Mt for the entire forest, with an average carbon storage of 133 t ha−1. The map showed that the distribution of TCS was heterogenic across the study area. Carbon hotspots were mostly composed of pure stands of Anatolian black pine and mixed, over-mature stands of Lebanese cedar and Taurus fir. It was concluded that the total carbon stocks of forest ecosystems could be estimated using appropriate SAR images at acceptable accuracy levels for forestry purposes. The use of additional ancillary data may provide more delicate and reliable estimations in the future. Given the implications of this study, the spatiotemporal dynamics of carbon can be effectively controlled by forest management when coupled with easily accessible space-borne radar data.

Forest Resource Potential of Cedar in the Far Fast

This paper studies the taxation indicators of previously developed standards for evaluating the productivity of Korean pine plantations. Rehabilitation of cedar stands is impossible without growth tables. The analysis shows that the productivity assessment of cedar trees as a renewable resource should be accompanied by working standards, bringing the plantings to a given goal. In other words, the norms should be compiled for a specific purpose, for example, the cultivation of nut plantations. Korean pine is a nut-bearing plant, and it is its most crucial production function for a wide range of consumers, including humans. At the moment, this formation was “not available” due to the overexploitation of raw (wood) resources in the last century. To return it to Russia’s renewable energy system in the next 30 years, it is necessary to review all functions to optimize them at different management levels. The analysis shows that with the help of modern technologies, it is possible to ensure the transition to a significant forest formation in various production areas, taking into account the demand for its products. This main transition elements are a high-quality regulatory framework, its compliance with the real capabilities of the formation, and favorable market conditions for products obtained from this formation. A bet on renewable energy sources will allow the world economy to avoid crisis periods, including those of a socio-ecological nature.

Fertility variation, seed collection and gene diversity in natural stands of Taurus cedar (Cedrus libani)

Seed stand is a natural forest population that is one of the essential seed sources for global seed supply. Individual fertility is an ability to produce progeny to next generation. Prediction of fertility variation is useful for seed quality, ecosystem management and gene conservation. Fertility variation and gene diversity in seed stands of Taurus cedar were estimated based on the difference in strobilus production between female and male parents. A total of 50 trees were randomly chosen from each stand, and female and male strobili were counted for three consecutive years. The mean of female strobili ranged from 31 to 150, and that of male ranged between 77 and 828. The variation in strobilus production was subjected to estimation of female and male fertility variation. The total fertility variation (\(\Psi\)) was estimated from the female and male fertility variation. The \(\Psi\) in a good crop year was smaller than in a poor year. The effective number of parents (Np) was calculated based on the \(\Psi\), which varied from 34.7 to 44.2. When strobilus productions were pooled across 3 years or populations, the Np increased. Equal cone harvest could mitigate the fertility variation among individuals but caused loss of seed production. Mixing seeds from different years could also decrease the fertility variation and increase the gene diversity of seeds. However, a balance between the size of Np and the number of pooling years should be carefully considered for maintaining the gene diversity in the natural stands.

Общие закономерности роста насаждений сосны корейской

В статье рассмотрены общие закономерности роста сосны корейской (Pinus koraiensis Sieboldet Zucc.) – ценнейшей древесной породы дальневосточных лесов. По данным анализов хода роста, таблицам хода роста разработаны типовые линии роста для четырех таксационных показателей: высоты, диаметра, видового числа и числа стволов. Они представлены в графическом и аналитическом виде. В основу метода построения таблиц хода роста положены индексные кривые. Korean cedar pine in the Khabarovsk Territory occupies 1,3 million hectares, which is 2,2 % of the area covered by forest. To control age-related changes in cedar stands S.N. Moiseenko in 1966 developed 28 tables of growth progress. The disadvantage of these tables is that they characterize the growth of plantations in the range of 110–330 years. One of the reasons for this age-related “isolation” was the lack of experimental material in this time period. The search for a solution to this problem led to the development of a method for constructing growth progress tables based on taxation indices calculated from trunk analysis data taken during growth. Indexes convey the general patterns of growth of stands of this breed and the interval of their action is 10–290 years. The advantages of this method include a limited number of typical growth lines according to the main taxation indicators – height, diameter, species number, number of trunks. Only one line of indices was developed for them. Minimization of typical growth lines, on the one hand, indicates the uniformity of the conditions for the growth of cedar-deciduous forests, and, on the other hand, allows us to simulate the growth progress of any tree stand we are interested in, regardless of its age, growth conditions, type of forest without felling of model trees. For the cedar formation, the method turned out to be the most relevant and progressive. His test on a high-productive tree stand showed acceptable practical possibilities when constructing growth tables.

Comparison of Parametric and Nonparametric Methods for Estimating Size–Density Relationships in Old-Growth Japanese Cedar (Cryptomeria japonica D. Don) Plantations

Accurately quantifying the size–density relationships is important to predict stand development, estimate stand carrying capacity and prescribe silvicultural treatments. Parametric methods, such as segmented regression, were proposed to estimate the complicated trajectory of size–density relationships. However, applying nonparametric methods to assess stand development has not been explicitly examined. In this study, we compared parametric and nonparametric methods for estimating size–density relationships for Japanese cedar plantations in Taiwan. Specifically, we compared the efficacy of two segmented regression models with the penalized spline and random forest for regression methods. We also examined various stages in stand development for old-growth Japanese cedar stands. Data collected from 237 Japanese cedar permanent plots were used in model fitting and validation. Results indicated that the parametric and nonparametric methods used in this study can provide reliable estimates of the size–density relationship for Japanese cedar. Higher accuracy was achieved before the stands diverged from the self-thinning line. The penalized spline approach behaved consistently well regardless of datasets or stages in stand development, while the predictability of the random forest algorithm slightly decreased when the validation data was fitted. The results of this study provide insights on the use of methods to quantify the size–density relationships as well as enhance the understanding of long-term stand development.

Evaluation of Individual Distance-Independent Diameter Growth Models for Japanese Cedar (Cryptomeria japonica) Trees under Multiple Thinning Treatments

Understanding the tree growth process is essential for sustainable forest management. Future yields are affected by various forest management regimes such as thinning; therefore, accurate predictions of tree growth are needed under various thinning intensities. This study compared the accuracy of individual-level distance-independent diameter growth models constructed for different thinning intensities (thinning intensity-dependent multiple models: TDM model) against the model designed to include all thinning intensities (thinning intensity-independent single model: TIS model) to understand how model accuracy is affected by thinning intensity. We used long-term permanent plot data of Japanese cedar (Cryptomeria japonica) stands in Japan, which was gathered from four plots where thinning was conducted at different thinning intensities: (1) intensive (41% and 38% of trees removed at 25 and 37 years old, respectively), (2) moderate (38% and 34%), (3) light (32% and 34%), and (4) no thinning. First, we specified high interpretability distance-independent competition indices, and we compared the model accuracy both in TDM and TIS models. The results show that the relative spacing index was the best competition index both in TDM and TIS models across all thinning intensities, and the differences in the RMSE (Root mean square error) and rRMSE (relative RMSE) in both TDM and TIS models were 0.001–0.01 cm and 0.2–2%, respectively. In the TIS model, rRMSE varied with thinning intensity; the rRMSE was the lowest for moderate thinning intensity (45.8%) and the highest for no thinning (59.4%). In addition, bias values were negative for the TIS model for all thinning intensities. These results suggest that the TIS model could express diameter growth regardless of thinning intensities. However, the rRMSE had varied with thinning intensity and bias had negative values in the TIS model. Therefore, more model improvements are required for accurate predictions of long-term growth of actual Japanese cedar stands.

Decreases in inorganic nitrogen inputs and effects on nitrogen saturation and soil acidification

ABSTRACT We aimed to elucidate the effects of decreases in nitrogen (N) inputs on N budgets and soil acidity in N saturated forests in Tokyo, Japan using new analysis and comparison to sampling data collected in the 1990s. Canopy throughfall and soil-percolated water samples were collected from stands of Japanese cedar (Cryptomeria japonica) and Japanese cypress (Chamaecyparis obtusa), where allophanic Andisols have developed. Stream water was sampled at the outlet of the catchment (2.15 ha). The total inorganic N input due to throughfall in the Japanese cypress stand was 104–184 mmolc m−2 year−1, which is a marked decrease from sampling results from the 1990s (1991–1992 and 1995). This decrease can be ascribed to a reduction in NOx emission from automobiles. Consequently, nitrate (NO3 −) outputs from the catchment decreased when compared with the previous study, although outputs were comparable to N inputs. Based on i) N budgets for the catchment and ii) episodic acidification of stream water, the study site remains N saturated. The degree of decrease in ammonium (NH4 +) inputs was larger than NO3 − inputs, which resulted in a decrease in acid production due to nitrification or plant uptake and contributed to reduced soil acidification. As a result, the pH values of soil-percolated water in the Japanese cypress stand increased slightly, compared to levels in the 1990s. On the other hand, soil pH values in the Japanese cypress stand were comparable to those in the 1990s due to the large acid-neutralizing capacity of allophanic Andisols.

ANALYZING CARBON STOCKS IN A MEDITERRANEAN FOREST ENTERPRISE: A CASE STUDY FROM KIZILDAG, TURKEY

ABSTRACT Carbon dioxide is one of the most important greenhouse gases responsible for global climate change. Terrestrial ecosystems are widely recognized as useful mechanisms, as they store large quantities of carbon in their bodies. In this context, the present study aims at analyzing carbon stocks in forest (both productive and degraded), grassland, and agricultural ecosystems of Kizildag Planning Unit. To this end, forest inventory data, published statistics, and GIS tools were used for modeling carbon densities of these three ecosystems in a spatially explicit manner. Moreover, carbon contents were estimated for different pools including above- and below-ground biomass, litter layer, deadwood, and soil components. Results showed that a total of nearly 3.5 million tons of carbon stored in the entire study area. When standardized to per unit area, productive and degraded forests stocked the most significant amounts followed by grassland and cropland land use/land cover (LULC) classes. The average density was 120.8 tons ha-1 for productive forests, while it was 32.3 tons ha-1 for croplands. The vast majority of these amounts stocked in soil pools for each LULC classes. Therefore, special attention should be paid for soil carbon studies which are very rare in the region. Regarding spatial distribution, Kizildag showed a rather non-homogeneous pattern in terms of carbon densities. Hotspots generally accumulated in the southwestern parts, as well as near the east border of the study area. Carbon densities could be as high as 200-245 tons ha-1 in these hotspots. Those areas were dominated by mixed stands of Taurus fir, cedar, and black pine at older ages and they were designated primarily for protective functions in the forest management plan. It is concluded that vast degraded forestlands in the region offer great opportunities to forest managers as an effective mechanism in combatting climate change. Therefore, rehabilitation, afforestation, and forest protection activities should be accelerated as possible.

Assessment of sanitary parameters of soils in cedar stands

The article presents the results of a study of the sanitary-microbiological parameters of soils in cedar stands on the example of the Vologda Oblast of Russia. The taxation description of cedar plantations showed that both urban and Siberian cedar plantings in the urban environment and beyond are distinguished by good growth. In the studied objects, the presence of phytopathogenic fungi dangerous for trees was found in soils, such as Aphanomyces, Fusarium, Phytophthora, Pythium, Verticillium, and the presence of saprotrophic fungi with antagonistic properties, such as Mucorales, Clonostachys, Trichoderma, Mortierella, Mucor. Phytopathogenic activity correlates inversely with the activity of saprotrophs-antagonists found in the zone of coexistence. According to microbiological indicators, the diversity of antagonistic fungi with signs of high suppression indicates the well-being of the studied soil samples. Based on the sanitary-microbiological assessment in the studied cedar groves, recommendations were developed and proposed for protecting soils in the cedar stands, such as selective forest protection measures, clearing of litter, and laboratory tests to determine the toxicity of soils that affect the growth and development of cedar stands.

Modeling Dominant Height Growth of Cedar (Cedrus libani A. Rich) Stands in Turkey

Abstract Sustainable forest management requires accurate prediction from a growth and yield system. Such a system relies heavily on some measure of site productivity, which is often the site index. A model was developed for predicting dominant height growth and site index of even-aged cedar (Cedrus libani A. Rich.) stands in Turkey. Stem-analysis data from 148 trees were used for model development and validation. Six dynamic height–age equations were derived using the generalized algebraic difference approach (GADA). Autocorrelation was modeled by expanding the error term as an autoregressive process. Based on numerical and graphical analysis, a GADA formulation derived from the Chapman–Richards model was selected. Based on relative error in dominant height prediction, 80 years was selected as the best reference age. The resulting equation provided the best compromise between biological and statistical aspects and, therefore, is recommended for height growth prediction and site classification of cedar stands in Turkey.