Annual Increment Research Articles

Effects of thinning on tree growth and soil physiochemical properties in Cunninghamia lanceolata plantation

ABSTRACT Tree growth, along with soil properties, is greatly affected by forest management. We used a typical sampling to study the impact of four thinning intensities (T1: 0%, 2500 stems ha−1; T2: 20%, 2010 stems ha−1; T3: 30%, 1750 stems ha−1; T4: 40%, 1500 stems ha−1) on the tree growth and soil physicochemical properties and their correlation in Cunninghamia lanceolata plantations. The average annual increments in tree height, diameter at breast height (DBH), and volume increased with thinning intensity, and those of T4 differed significantly (P < 0.05) from those of T1. The average annual stand volume increments of T4 were significantly (P < 0.05) lower than that of T1, while the maximum value presented at T3. However, the effect of thinning in promoting the growth of Chinese fir diminished with time. As the thinning intensity increased, the diameter class distribution of the sample stands moved rightwards. Moreover, thinning improved soil physiochemical properties. The effects of thinning on soil properties in 0–20 cm soil layer were greater than those in 20–40 cm soil layer. There was a positive correlation between available nitrogen, available potassium and tree growth. The results of this study showed that thinning had a potential effect on tree growth and soil properties. The heavy thinning intensity (approximately 1500 stems ha−1) was the optimum for maintaining economic and ecological benefits. However, heavy thinning significantly reduced stand volume. From the perspective of improving stand volume and biomass, a moderate thinning intensity (approximately 1750 stems ha−1) could be considered for adoption.

Age and Growth Estimation of Bigeye Tuna, Thunnus obesus (Lowe, 1839) in the Eastern Indian Ocean Deduced from Otolith Microstructure

Age-based stock assessment of globally important species, like bigeye tuna Thunnus obesus (Lowe, 1839), is urgently required to develop appropriate management plans for fisheries sustainability. This study aimed to estimate age and growth parameters using annual increments count of sectioned-otoliths, which effectively employed for age determination of tunas. Samples were collected from Indonesian tuna longline catch landed in the Port of Benoa from March until December 2017. Multi-models were employed to obtain robust growth parameters, and Akaike Information Criterion (AIC) was relied for the best fit model selection among those evaluated. Growth band formation was validated using marginal analysis (MI), indicating that one ring is deposited yearly and slow growth peaked during July (Australian winter). The von Bertalanffy growth model was selected as the best model fitting growth parameters from raw age data, as expressed as Lt = 183.49 (1-e-0.134(t+2.991)). Large variances in growth were detected at the same age, with the oldest age of 15. Over 50% of fish in the Indonesian catch were &lt;5 years old, that may have implications for fisheries sustainability.

Trace of negative changes in environment recorded in cores of trees growing near busy city roads in Poznań, Poland – dendromonitoring of urban pollution

Dendromonitoring helps answer the question of how polluted cities are and how this pollution will change over the years. However, due to many possible over-interpretations of the obtained results, it is necessary to understand the deposition processes of pollutants in trees thoroughly. Thus, the aim of this study was to determine the mineral composition of the wood of 3 common deciduous tree species: Norway maple (Acer platanoides L.), silver birch (Betula pendula Roth.), and black poplar (Populus nigra L.) growing near the busiest roads in Poznań, Poland. The research material consisted of core fragments containing the annual increments collected at the breast height of living trees. The content of 22 elements (Al, Ba, Ca, Cd, Cr, Cu, Fe, K, Mg, Mn, Mo, Na, Nd, Ni, Pb, Pr, Rb, Sb, Sr, Ti, Tl, and Zn) in the obtained samples together with the determination of the number of annual increments and density of 3 cm wood fragments were presented. The obtained results indicated an overall increase in the content of determined elements from the pith to the cambium layer. The range of the examined elements was extensive, and it was not found that one particular species accumulated the most of all the elements. Acer platanoides accumulated the highest concentration of 13 (Ca, Cd, Cu, Fe, K, Mg, Mo, Na, Nd, Ni, Pb, Sr, and Ti), B. pendula of 3 (Ba, Mn, and Zn), and P. nigra of 6 (Al, Cr, Pr, Rb, Sb, and Tl) elements. Despite the growth of individuals of the same species in different parts of the city, a general trend associated with the increase in the content of most elements was observed. We can assume that the concentration increase indicated in our study reflects the increasing degree of pollution in the urban environment over 30 years.

Study on the response relationship between land use and eco-environmental quality - a case study of Jing-Jin-Ji urban agglomeration

In view of the complexity of traditional eco-environmental quality evaluation index system and the time-consuming calculation, this paper used remote sensing ecological index (RSEI), combined with MODIS products and GEE platform, to quantitatively evaluate the eco-environmental quality and land use in Jing-Jin-Ji from 2010 to 2020, and analysed the response relationship between eco-environmental quality and ecological land. The results showed that: 1) The eco-environmental quality in Jing-Jin-Ji showed a “V” shaped change trend in the past ten years, with its average value first decreased from 0.51 to 0.46, and then increased to 0.48; 2) The dynamic degree of arable and grass land in Jing-Jin-Ji was negative, while forest land was positive. The average annual increment of construction land was the highest (638.72 km2•y−1); 3) There existed good consistency between the average RSEI value and the change trend of ecological land in Jing-Jin-Ji, but the change rate was not synchronous, which showed that the increased rate of ecological land was higher than the decreased rate, while the increased rate of the average RSEI value was significantly lower than the decreased rate, reflecting that the recovery rate of eco-environmental quality was lower than the degradation rate.

Climate change-related growth improvements in a wide niche-breadth tree species across contrasting environments.

The vulnerability and responsiveness of forests to drought are immensely variable across biomes. Intraspecific tree responses to drought in species with wide niche breadths that grow across contrasting climatically environments might provide key information regarding forest resistance and changes in species distribution under climate change. Using a species with an exceptionally wide niche breath, we tested the hypothesis that tree populations thriving in dry environments are more resistant to drought than those growing in moist locations. We determined temporal trends in tree radial growth of 12 tree populations of Nothofagus antarctica (Nothofagaceae) located across a sharp precipitation gradient (annual precipitation of 500-2000 mm) in Chile and Argentina. Using dendrochronological methods, we fitted generalized additive mixed-effect models to predict the annual basal area increment as a function of year and dryness (De Martonne aridity index). We also measured carbon and oxygen isotope signals (and estimated intrinsic water-use efficiency) to provide potential physiological causes for tree growth responses to drought. We found unexpected improvements in growth during 1980-1998 in moist sites, while growth responses in dry sites were mixed. All populations, independent of site moisture, showed an increase in their intrinsic water-use efficiency in recent decades, a tendency that seemed to be explained by an increase in the photosynthetic rate instead of drought-induced stomatal closure, given that δ18O did not change with time. The absence of drought-induced negative effects on tree growth in a tree species with a wide niche breadth is promising because it might relate to the causal mechanisms tree species possess to face ongoing drought events. We suggest that the drought resistance of N. antarctica might be attributable to its low stature and relatively low growth rate.

Effects of thinning on tradeoffs between drought resistance, drought resilience, and wood production in mature Douglas-fir in western Oregon, USA

Climate projections predict more frequent and severe drought in coastal Pseudotsuga menziesii forests of western North America, raising concerns over how to promote drought adaptation. Thinning often increases drought resistance (the ability to maintain growth during a drought) and resilience (the ability to recover growth after a drought), but these effects vary with thinning intensity, shift over time, and may have tradeoffs with fiber production. We collected tree cores from a long-term thinning study with four residual density levels replicated across both uniform thinning and thinning with gaps, and used annual growth data to investigate responses to droughts occurring 8 and 21 years after thinning. For the first drought, resistance and resilience were higher in treatments with lower residual densities. For the second drought, there were no differences in drought response between the lowest and highest residual density treatments, and all treatments had lower drought resistance and resilience than for the first drought. Spatial arrangement had little impact on drought resistance or resilience and residual density level had a significant effect on the periodic annual volume increment—drought resistance tradeoff. Our results suggest that thinning can promote drought adaptation in Pseudotsuga menziesii forests, but these effects dissipate over time.

Diametric Growth of a Forest under Reduced-Impact Logging in the Eastern Region of the Brazilian Amazon

Growth is a component of forest dynamics that encompasses changes in species composition, interactions between species, and stand structure. We evaluated the effect of the presence of lianas, crown shape, and light exposure on the periodic annual increment of trees (PAI) in two phytophysiognomies: the ombrophilous dense forest and the ombrophilous open forest with lianas. This study was conducted in the eastern Brazilian Amazon in 13 permanent monitoring plots of 50 m × 50 m (2500 m2) in the same annual production unit. The area has been subjected to reduced-impact logging from 2014 to 2016. The increment in tree diameter varied significantly between both forests (opens forests: 1.28 cm yr−1; dense forests: 0.82 cm yr−1). Light exposure influenced the increment in tree diameter in the ombrophilous open forest with lianas, while the crown shape and light exposure significantly affected the ombrophilous dense forest. Our study emphasizes the usefulness of the periodic annual increment in exploring the differences between contrasting phytophysiognomies in a single annual production unit in the Brazilian Amazon that is subject to reduced-impact logging.

Spatial comparisons of productivity and carbon sequestration for Cupressus lusitanica and macrocarpa within New Zealand

Cupressus lusitanica and C. macrocarpa are two fast growing conifer species with valuable timber that have been widely established throughout New Zealand. Despite the importance of these two species within New Zealand and in many other countries, little research has investigated how volume, height, and carbon productivity are influenced by environment. Volume growth of these two cypress spp. has been recently described using the 300 Index which quantifies the mean annual volume increment at age 30 yrs for a stand density of 300 stems ha−1. Using New Zealand growth data obtained from 290 plots, the objectives of this study were to (i) develop models and fine resolution national maps of 300 Index and site index, (ii) use these two productivity metrics and allometric equations to develop models of carbon stocks for the two species, and (iii) spatially predict carbon across New Zealand for C. lusitanica and macrocarpa grown under a factorial range of stand densities (400, 650 and 900 stems ha−1) and ages (30, 40 and 50 yrs).Plot measurements showed wide variation in 300 Index which reached 26.9 and 29.0 m3 ha−1 yr−1, respectively, for C. lusitanica and C. macrocarpa. Site index (age 30 yrs) reached values of 31.9 and 34.1 m for C. lusitanica and C. macrocarpa, respectively. Models developed for C. lusitanica had high accuracy for both 300 Index (RMSE = 2.48 m3 ha−1 yr−1; R2 = 0.75) and site index (RMSE = 1.78 m; R2 = 0.84) while models developed for C. macrocarpa had similar, but slightly lower, accuracy for 300 Index (RMSE = 2.86 m3 ha−1 yr−1; R2 = 0.72) and site index (RMSE = 1.86 m; R2 = 0.81).Spatial predictions of the two productivity metrics showed distinct differences between species with C. lusitanica being more sensitive to cold, dry, and wet conditions than C. macrocarpa. Under the mid-range scenario (age 40, 650 stems ha−1) mean carbon sequestration in above and below ground biomass, dead wood, and litter pools for C. macrocarpa was higher than C. lusitanica in both the North Island (321 vs. 296 t C ha−1) and South Island (222 vs. 120 t C ha−1). Carbon was higher for C. macrocarpa than C. lusitanica within, respectively, 62 and 94% of the North and South Islands under the mid-range scenario. Carbon markedly increased with stand density and age and gains were greatest between ages 30 and 40 and from the low to moderate stand density for both species.

Multi-site comparison of clonal arrangements for tropical and subtropical hybrids of Eucalyptus

The definition of the ideal eucalyptus clonal arrangement directly affects the forest industrial chain, quality of products, and stand yield. The impact of eucalyptus in mono- versus multiclonal stands on plantation production and sustainability has been frequently discussed by primary stakeholders within the pulp industry, but few studies have examined this topic through direct comparison. In this study, we evaluated the differences in genotype ranking and yield of Eucalyptus spp. and clones displayed in mono- and multiclonal arrangements. In this context, the objectives addressed were: (i) to estimate genetic parameters in multi-environment and site-by-site analyses; (ii) to predict genotypic values of clones and the effects of species in mono- and multiclonal experiments, and (iii) to compare the similarity between the ranks of clones and species in the two types of clonal stands. The study was conducted in 2018 at four different sites of the CMPC Celulose Riograndense company, located in the state of Rio Grande do Sul, Brazil. Mono- and multiclonal arrangements were tested at each site, involving 33 eucalyptus clones belonging to 10 species and hybrids. Multiple-tree-plot (MTP) and single-tree-plot (STP) experiments were used to simulate monoclonal stands and multiclonal or composite stands, respectively. In each experiment, a randomized block design was set with three repetitions, 16 plants per plot for MTP, and 24 repetitions and one plant per plot for STP. Traits monitored were diameter at breast height (DBH), total height (H), tree volume (VOL), mean annual volume increment (MAI), and survival (SUV). Data were analyzed using mixed model approaches, considering a normal distribution for growth traits and a binomial family for survival. There was a strong genotype × site interaction for all traits, indicating that edaphoclimatic conditions must be considered for the successful establishment of clonal composites of differing genotypes. There was high similarity in the classification of clones in both mono- and multiclonal experiments, with genetic correlation values above 0.90. The performance of clones differed in mono- and multiclonal experiments, which correlated with their competition behavior toward each other (aggressive, suppressed, or homeostatic). Thus, clonal composites can be recommended based on clonal competition and genetic heterogeneity to maximize the yield of the stand and safeguard the plantations from biotic and abiotic disturbances. This study allowed us to identify the differences between the two types of commercial stands and provide direction for future research regarding the performance of Eucalyptus spp. in differing clonal arrangements. Novel information about competition categories for different eucalyptus tropical and subtropical species were provided.

PHYTOPATHOLOGICAL MONITORING OF DANGEROUS OUTBREAKS DISEASE OF FOREST TREES WITH USE METHOD OF CHANGING RADIAL INCREMENTS IN THE CONDITIONS OF THE POLISKY NATURE RESERVE

PHYTOPATHOLOGICAL MONITORING OF DANGEROUS OUTBREAKS DISEASE OF FOREST TREES WITH USE METHOD OF CHANGING RADIAL INCREMENTS IN THE CONDITIONS OF THE POLISKY NATURE RESERVE

Advanced Method of Variable Refrigerant Flow (VRF) System Design to Forecast on Site Operation—Part 3: Optimal Solutions to Minimize Sizes

Outdoor air conditioning systems (ACS) are used as autonomic systems as well as in combined outdoor and indoor ACS of the variable refrigerant flow (VRF) type, with variable speed compressors (VSC) as their advanced version. Methods for determining the optimal value of refrigeration capacity and providing the maximum rate of the summarized annual refrigeration energy generation increment, according to its needs at minimum compressor sizes and rational values, are applied to reveal the reserves for reducing the designed (installed) refrigeration capacity, thus enabling us to practically achieve maximum annual refrigeration energy generation as the primary criterion at the second stage of the general design methodology previously developed by the authors. The principle of sharing the total thermal load on the ACS between the ranges of changeable loads for outdoor air precooling, and a relatively stable load range for further processing air are used as its basis. According to this principle, the changeable thermal load range is chosen as the object for energy saving by recuperating the excessive refrigeration generated at lowered loading in order to compensate for the increased loads, thereby matching actual duties at a reduced designed refrigeration capacity. The method allows us to determine the corresponding level of regulated loads (LRL) of SRC and the load range of compressor operation to minimize sizes.

Spatial and Temporal Distribution of Near-Surface Methane Concentration in Northwest China Based on GOSAT Satellite Data

Methane (CH4) is a common greenhouse gas that plays an important role in global warming and affects people’s production and life. In order to study the temporal and spatial distribution situation of methane concentration in northwest China (Shaanxi, Gansu, Ningxia, Xinjiang, Qinghai), this article used L4B level data products monitored by GOSAT satellite from 2009 to 2019 to study the temporal and spatial distribution characteristics of near-surface methane concentration in northwest China. The results of the analysis were as follows. Firstly, the annual average concentration of near-surface methane in northwest China was in a rising state, and the maximum annual average concentration increment was in 2016. Secondly, seasonal variation of methane concentration: Autumn>Summer>Spring>Winter. Finally, spatial variation of the annual average methane concentration: Shaanxi, Ningxia, and southern Gansu>northwest Xinjiang>other northwest China regions. The methane concentration decreased from the bottom to the top gradually.

Importance and potential of Scots pine (Pinus sylvestris L.) in 21st century

Abstract We are currently witnessing significant global changes in climate conditions. We cannot change the natural conditions, but with regard to sustainable landscape management, we can increase our knowledge of tree species and adapt forest management to them. Surprisingly, one of the most affected tree species in Central Europe today is Scots pine (Pinus sylvestris L.). The following literature review summarizes over 200 studies from 1952–2022 regarding Scots pine across its entire range while addressing various topics in the ecology and management of this taxon. It is a tree species with a large natural range, nearly covering the entire Eurasian area. In the Czech Republic, it is the second most important tree species in terms of industrial wood production. Scots pine is characterized not only by a significant genetic variability of its populations but also by its wide ecological plasticity. Typically, it grows on sandy soils, poor habitats, and stony scree–but also in peat bogs. The wide habitat valence justifies the economic significance of this species, both in terms of its high production potential (mean annual increment of up to 10.8 m3 ha-1 yr-1) but also its wide range of use. However, in the light of climate variations, the practices of Scots pine silviculture are also gradually transforming from the traditional reforestation by clear-cutting to a more natural system–shelterwood felling. In view of climate change, its range of distribution is changing, as with other species, but Scots pine remains a very resistant tree species, depending on the habitat.

Carbon Sequestration in Resin-Tapped Slash Pine (Pinus elliottii Engelm.) Subtropical Plantations

Every year more than 150,000 tons of resin used in a myriad of industrial applications are produced by Brazilian plantations of Pinus elliottii Engelm. (slash pine), which are also used for timber. A pine tree can be tapped for resin over a period of several years. Resin is a complex mixture of terpenes, which are carbon-rich molecules, presumably influencing pine plantation carbon budgets. A total of 270 trees (overall mean DBH of 22.93 ± 0.11 cm) of 14-, 24-, and 26-year-old stands had their C content measured. Three different treatments (intact, wounded panels, and wounded + chemically stimulated panels, 30 trees each) were applied per site. Above- and belowground biomass, as well as resin yield, were quantified for two consecutive years. Data were statistically evaluated using normality distribution tests, analyses of variance, and mean comparison tests (p ≤ 0.05). The highest resin production per tree was recorded in the chemically stimulated 14-year-old stand. Tree dry wood biomass, a major stock of carbon retained in cell wall polysaccharides, ranged from 245.69 ± 11.73 to 349.99 ± 16.73 kg among the plantations. Variations in carbon concentration ranged from 43% to 50% with the lowest percentages in underground biomass. There was no significant difference in lignin concentrations. Soils were acidic (pH 4.3 ± 0.10-5.83 ± 0.06) with low C (from 0.05% to 1.4%). Significantly higher C stock values were recorded in pine biomass compared to those reported for temperate zones. Resin-tapping biomass yielded considerable annual increments in C stocks and should be included as a relevant component in C sequestration assessments of planted pine forests.

Modelling the Development of Above-Ground Biomass Energy Reserves of Four Economically Important Coniferous Woody Species

The goal of renewable energy is to replace energy production from fossil fuels. In that sense, forest biomass is essential renewables. This article presents the results of the development of energy reserves in fractions, increments and the total above-ground biomass of coniferous stands (spruce, fir, pine, larch) during their economic cycle. The experimental material comes from 22 forest stands located mainly in Central Slovakia, to a lesser extent also in Western and Eastern Slovakia. Energy reserves of coniferous stands were calculated based on the volume production of above-ground biomass fractions taken from mathematical models of yield tables and average values of their basic density and calorific value were determined. The research showed that as the age of the stands increased, the share of energy in the wood fraction increased, while it decreased in the bark fraction, and especially the branch fraction. The curves constructed in relation to the age of the stand and site index have a very similar shape to the curves of the total current annual energy increment of coniferous stands. The energy reserves of stands grew faster at the age of 40 to 80 years than at the age of 80 to 140 years. Spruce had the highest total mean energy increment, followed by fir, larch and pine. As the age of the stands increases, the energy reserves of the increments slightly decrease and the efficiency of solar energy significantly decreases. It peaks practically at the age of reaching the maximum annual energy increment.

Fire-caused mortality within tree neighborhoods increases growth of Pinus lambertiana more than growth of Abies concolor

Global increases in large-tree mortality and multiple disturbances such as fire, drought, and pestilence increase the importance of understanding how large-tree growth responds to changes in competitive neighborhoods. We used 34,175 spatially mapped trees within 25.6 ha that burned at low to moderate severity in 2013 to investigate how changes to tree neighborhoods affected growth of 3,652 surviving trees of two species, Abies concolor (white fir) and Pinus lambertiana (sugar pine). Using diameter measurements taken in 2014 and 2019, we estimated post-fire radial growth of each surviving tree. We modeled annual basal area increment as a function of diameter and extracted residuals to yield relative growth rate (RGR). We used a multi-model approach and AIC to compare the species-specific effects on RGR of all post-fire tree mortality within a neighborhood radius versus mortality broken down by cause. To represent density reduction around each surviving tree, we computed crowding metrics for neighborhood radii up to 20 m for all tree mortality combined and for each mortality cause. The best-fit model included terms for density reduction within 10 m of the surviving tree due to 1) fire or mechanical damage and 2) bark beetle mortality, as well as their interactions with species and diameter. Density reduction due to fire or mechanical damage had a positive effect on RGR that was nearly twice as strong for P. lambertiana as A. concolor. Tree diameter interacted with density reduction for just P. lambertiana. Small-diameter (10-cm) P. lambertiana had a fourfold larger increase in basal area increment than large-diameter (60-cm) P. lambertiana as density reduction due to fire or mechanical damage ranged from 0 to 100 %. The strong growth response of medium-diameter P. lambertiana to density reductions could eventually increase the abundance of large-diameter (≥60 cm) P. lambertiana. In conjunction with mortality rates, which were lower for large-diameter P. lambertiana (0.97 %) than A. concolor (3.31 %), this could increase the relative abundance of large-diameter P. lambertiana from 51.2 % in 2020 to 62.6 % by 2050. Changes to competitive neighborhoods can have species-specific effects on large-tree growth, an important consideration for long-term management of fire-prone forests.

Comparison of carbon content between plantation and natural regeneration seedlings in Durango, Mexico.

Forest plantations and natural forests perform a relevant role in capturing CO2 and reducing greenhouse gas concentrations. The objective of this study was to compare the diameter increment, biomass and carbon accumulation in a plantation of Pinus durangensis and a naturally regenerated stand. The data were collected from 32 circular plots of 100 m2 (16 plots in the planted site and 16 in naturally regenerated area). At each plot, the diameter at the base (cm) and height (m) of all seedlings were measured using a Vernier and tape measure, and a seedling was destructively sampled collecting one cross-section at the base of the stump. The annual ring-width increment of each sampled seedling was recorded to obtain its diameter at the base and estimate annual aboveground biomass and carbon accumulation through allometric equations. The response variables were evaluated using mixed-effects ANOVA models. Results indicated that there were significant differences (P ≤ 0.05) on annual tree-ring width growth, biomass and carbon accumulation. The plantation seedlings showed significantly higher growth rates, biomass and carbon accumulation at most evaluated years. After 7 years of growth the lines of current annual increment (CAI) and mean annual increment (MAI) in basal diameter for both the plantation and the natural regeneration have not yet intersected. Both forest plantations and naturally regenerated stands of the studied tree species may be suitable alternatives to promote CO2 capture and increase timber production.

Rice demand and production projections for 2050: Opportunities for achieving self-sufficiency in Nepal

Rice is a major food, contributing 67% of cereal consumption in Nepal. It is playing a substantial role in food and nutritional security. Rice production is not sufficient to meet domestic consumption, so its import has been increasing. This study aims to explore whether Nepal can be self-sufficient in rice production in the current context of increasing rice demand and changing climate. We assessed the degree to which Nepal can be self-sufficient in rice production by the years 2030, 2040, and 2050, evaluating 12 different scenarios of demand driven by production, population growth, income, and climate change effect. We used compound growth rate estimation for analyzing the growth of rice production and population growth over time. Auto-regressive regression model was used to analyze the relationship of rice import and demand with domestic production, income, and population. A significant (p=0.000) positive impact of income on the import of rice was estimated, whereas significantly (p=0.000) higher impact of production on demand was estimated compared to income. Based on current rice productivity growth of 1.47% and population growth of 1.3% per year over three decades, the country will not achieve self-sufficiency until 2050.The situation would be further worsened in climate change scenarios. However, integrating the population growth rate of the last decade (0.57% per annum) with two productivity growth rate scenarios (current and (ii) 5% annual increment), the country can be self-sufficient by 2040. Based on different scenarios, the estimated demand can be met by increasing current productivity by at least 27–43% by 2030 and 42–85% by 2050. The study identified major gaps and opportunities in the rice production systems of Nepal and provided evidence-based solutions to meet the future demands in the context of increasing population and income, declining land availability, and high vulnerability to climate change.

Tree Growth and Vegetation Diversity in Northern Idaho Forest Water Reclamation Facilities

Forest water reclamation can improve tree growth and renovate municipal wastewater. Although there are indications that long-term application may exceed forest assimilation capacity, there is limited information on the long-term effects of reclaimed water application on coniferous ecosystems. The purpose of our study was to assess the impacts of prolonged reclaimed water application on forest growth responses and vegetation diversity. We examined the effects of reclaimed water at five water reuse facilities established between 1978 and 2013 in a four-decade time series. We collected tree cores and stem measurements to determine current and retrospective increments. We assessed plant diversity with vegetation surveys. The greatest diameter response observed for reclaimed water amendment compared to controls was 166.1% for western redcedar, while Douglas-fir increased up to 116.4% and ponderosa pine increased up to 100.6%. The minimum response observed was 30.3%. Current annual increments showed that the basal area and volume were significantly greater at long-established facilities for reclaimed-water-amended plots. The understory vegetation diversity declined with application time, while overstory vegetation diversity increased with application time. We conclude that reclaimed water can be a valuable resource to improve forest productivity, but continued application without stocking control may have detrimental effects on forest growth and vegetation diversity.

Wood density variations of E. urophylla clone among growth sites are related to climate

The Eucalyptus genus is extensively planted in Brazil for industrial use, and with the expansion of forest frontiers and climate changes, studies are needed on how these changes affect wood density (WD). The aim of this study was to evaluate the effect of some climate variables on WD of an Eucalyptus urophylla clone for a 4–5 year period. WD from trees collected in 12 sites were evaluated. Five growth rings were identified using a magnifying glass, X-ray densitometry, and forest inventory. WD was correlated with temperature ( T), precipitation ( P), soil water deficit, ring width, and current annual increment. There was no variation in WD in the first 20 months among sites. From that age on, WD was mainly correlated with T ( r &gt; 0.6). The 1 °C increase in T resulted in a WD reduction of 0.014 g cm−1, and increases of 10 m³ ha−1 in the final volume were related to an increase of 0.004 g cm−1 in WD. Researchers and managers should continue to put efforts into broad experimental networks to assess the effects of climate change on the adaptation and wood quality of Eucalyptus clones. Highlights The influence of climate on E. urophylla wood density was greater after the third year of growth. The mean air temperature was the best correlated climatic variable with E. urophylla wood density. The cross-site climatic gradient was more important in wood density variation of E. urophylla than the variability among the years.