EFFECTS OF METEOROLOGICAL VARIABLES ON Pinus caribaea GROWTH IN DIFFERENT AGES AT THE AMAZON REGION.

This study compares the impact of five meteorological variables on the diametric growth of Pinus caribaea var. hondurensis Barrett & Golfari in Vilhena, Rondônia. One thousand nine hundred sixty-eight trees were evaluated and classified at different ages: 600 trees were one year old; 600 trees were two years old; 768 trees were 13 years. The diameter measurement at the soil level (SL) was conducted in young stands between one and two years old. In the stand with 13 years old, the diameter was measured at 1.3 m (DCH). Using a Pressler borer, 50 increment cores were removed at DCH to measure the tree rings in LINTAB™ 6. The diametric growth was evaluated through the Periodic Increment (PI) for young stands and Current Annual Increment (CAI) for adult stands. The following variables were considered: average temperature (°C), precipitation (mm), solar radiation (Kj m-²), real evapotranspiration (mm), and maximum relative humidity (%). The Pearson Correlation Coefficient (r) proposed by Callegari-Jacques and the coefficient of variation (CV%) were used to establish the relationship between growth and meteorological variables. For young stands, the variables with higher positive correlation were real evapotranspiration and maximum relative humidity. However, the variable with a higher positive correlation in adult stands was average temperature, demonstrating a strong correlation until the sixth year of the species.

PRUNING Araucaria angustifolia FOR KNOT-FREE TIMBER PRODUCTION

Although A. angustifolia is currently economically unimportant, the worldwide trend of conservation through the sustainable use of natural resources together with an intense discussion of governmental regulations and the recent results of genetic breeding started in the 1970s are delivering promising perspectives for a new wave of plantations. This study aimed to determine optimal pruning strategies by evaluating the diameter and height growth of young A. angustifolia trees as affected by different pruning intensities. Pruning quality in terms of occlusion and defect-core size were also investigated. At the age of 6 years, the pruning experiment was started by conducting six different pruning intensities, named after the number of whorls left after pruning (0, 2, 4, 6, and 8), as well as unpruned (U) trees as a control. From the results obtained in the present study, it was concluded that pruning intensity had a significant negative effect on the growth of young A. angustifolia trees. Diameter was more affected than height growth. Pruning young A. angustifolia trees for knotty-free timber production must be conducted keeping 8 whorls after the intervention if no negative effect in current annual increment in diameter is to be observed when compared to unpruned trees. A defect core of 15 cm seems to be a feasible target for the species regarding optimal pruning intensity to avoid losses in diameter growth. This is strongly dependent on a fast occlusion process, which, in turn, is a result of a careful pruning technique.

Betula pendula Ssp. distribution and growth in the sub-Carpathian curvature

Birch ssp. in the sub-Carpathians curvature can be found in composition with beech and other resinous species, unevenly distributed from the mountain peaks at around 1200 m down to 500-600, mainly from high hills to depressions at 600m, rarely seen on plain sites, crossing different geomorphological structures and overall accounting for 3857.1 ha. The main objective of the paper was to analyze the site and stand characteristics of Betula pendula ssp. Roth. in the subCarpathians curvature as followed: stand structure, stand types and stand site types, soils and different metrics, from growth to yields and its connectivity.The ecological adaptability to climate and soil and early fast growth, makes silver birch fulfill the overall requirements as a pioneer species, mostly naturally regenerated. Birch distribution is highly influenced by stand structure having low proportion in compositions, mean height of 15 m at age 50, and a diameter of 20m. Regarding the site, characteristics are more commonly found on fertile soils, corrugated or fragmented site type with a slope of 20-50° and it is distributed as secondary species in stands, averaging 750m in attitude, ranging from 500 to 1200m, 90% being in mixtures with other species with a mean annual increment of approximately 7 m³/year/ha regardless of stand site type. As an early successional species, it serves as a first colonizer but secondary species and quite often as an ecological instrument to improve the soil characteristics, biodiversity and prevent landslides in certain sites, lacking economic value other than fuel wood or other non-wood products.

Trend Analysis of Climatic and Hydrological Parameters in Ajora-Woybo Watershed, Omo-Gibe River Basin, Ethiopia

BackgroundIdentifying hydro-meteorological trends is basic for assessing change in climate and river discharge at watershed level. This study examined the long-term trends of rainfall, temperature, and discharge in the annual, monthly and seasonal time scale of Ajora-Woybo watershed in Ethiopia. The data span of rainfall and temperature is between 1990 and 2020 and that of discharge is between 1990 and 2015. Homogeneity test was performed by using Pettit and SNHT tests. Then Mann-Kendall and Sen's slope test for trend analysis and different variability measures were used. ResultsResults indicate that inhomogeneity was detected in annual rainfall data of Angacha and Areka stations. On annual basis, rainfall and discharge exhibited insignificant trends over time while showing a general decreasing pattern. On monthly basis, February and March were found to have significantly decreasing trend for rainfall. During the Kiremt season, rainfall increases and discharge decreases insignificantly. In contrast, maximum, minimum and mean annual temperatures exhibited significant trends with annual increment of 0.04oC, 0.01oC, and 0.025 oC per year respectively. Correlations of discharge with both temperature and rainfall have found to be weak in this study.ConclusionsThis trend, combined with population growth and increasing demand of water for agricultural activities exacerbates competing demands for water resources. Caution is therefore required when it comes to developing appropriate measures for the planning and sustainable development of the water resources in the watershed.

Growth of Palm Trees and Woods in the Urban Environment

Trees in the urban environment provide several ecosystem benefits to the population, such as decreasing temperature, increasing humidity, shading, improving air quality, as well as physical and mental well-being. These can be enhanced through the knowledge of the growth of the trees in function of the characteristics of the place where they are inserted. Thus, the objective was to estimate the growth in diameter, height and volume of forest species in the urban environment, in Viçosa, Minas Gerais, Brazil. For this, woody individuals and palm trees present in the urban afforestation of the headquarters campus of the Federal University of Viçosa were selected based on age and had their diameter, breast height and height measured. Allometric equations specific to the study site were used to estimate their volume, and through the relationship with age, the average annual increment was obtained. Woody individuals showed a growth rate in volume of 0,0279 ± 0,0274 m³ year-1 and palm trees, 0,0139 ± 0,0119 m³ year-1. The differences in the average annual increase in volume found between woody individuals and palm trees may be due to morphological differences that affect the secondary growth of individuals. The growth rate of trees in the urban environment is higher when compared to those in forest fragments and experimental plantings. The decrease in growth rates with increasing age was expected due to the relationship between them being of the non-linear type, following a sigmoidal model.

Growth assessment of upper hill dipterocarp (Shorea platyclados) at the various slope in a rehabilitated landscape

Rehabilitation aims to improve landscape function while increasing its resilience to climate change. Gunung Dahu research forest is a rehabilitated hilly landscape that is planted with more than 25 dipterocarp species, including an upper hill dipterocarp tree of Shorea platyclados at various site conditions. This study aimed to assess the growth performance of S. platyclados at five sloping levels class of 0-8%, 8-15%, 15-25%, 25-45%, and >45%. Observed growth attributes were stem diameter, total height, basal area, Mean Annual Increment (MAI), and Leaf Area Index (LAI), and diameter. The results showed that sloping levels significantly affect the growth performance of the planted trees. The highest slope level (>45%) supported the highest average stem diameter and tree height (41.48 cm and 20.86 m). The sloping level of >45%, 25-45%, 15-25%, 8-15%, and 0-8% yield different value of average diameter which were 41.48 cm, 35.86 cm, 36.54 cm, 34.61 cm, and 31.23, while the average height were 20, 86m, 19.78 m, 16.72 m, 18.84 m, 18.61 m respectively. Thus, the upper hill dipterocarp of S. platyclados is a prospective native tree species for rehabilitating hilly upland landscapes.

The growth performance of dipterocarps species and understorey diversity in the Gunung Dahu Research Forest, Leuwiliang, Bogor

Dipterocarps species is the main species composes Gunung Dahu research forest. Habitat suitability and growth performance of a species are some factors considered in the species selection for forest establishment. The understorey in a forest community serves to protect soil from erosion. This research aimed is to analyze the growth performance of various Dipterocarpaceae species and study understorey diversity in the research area. The measurement was conducted in four species trial plots contain ten Dipterocarps species consist of five individuals per species per plot or 200 individuals in total. The growth performance of Dipterocarp species was analyzed using the current annual increment (CAI) and mean annual increment (MAI) methods. The understorey diversity was analyzed using the Shannon-Wiener Index. The result showed that Shorea johorensis obtained the highest CAI, 0.95 cm year−1, and Shorea platyclados got the highest MAI, 1.78 cm/year. S. platyclados and S. leprosula were projected to reach <40 cm in diameter after they got 25 years. The Gunung Dahu research forest’s understorey was classified as moderate (1.68 - 2.33). The dominant understorey species, namely Oldenlandia auricularia, Neprolephis biserrate, Ottochloa nodosa, and Gleichenia linearis. This study concluded that the growth performance of Dipterocarps species in the study area varied, and the understorey condition was classified as moderate, where its diversity has a positive correlation with the crown openness.

The growth Shorea leprosula Miq. on various slopes and directions of slopes in Gunung Dahu Research Forest, Bogor

Shorea leprosula Miq is a Dipterocarps forest plantation that has the prospect of being developed because it is a fast-growing species with high economic value. Given its commercial importance, this study was conducted to analyze the effect of slope class and slope direction on growth. Data were collected using the census method on S.leprosula stands with a spacing of 2m x 2m and 4m x 8m. The direction of the slope is determined based on the configuration of the slope according to the cardinal directions, while the slope of the land is determined based on the classification of the slope class of the land. The results showed that the slope class, slope direction, and the interaction between factors had a significant effect on the growth of S.leprosula. The interaction between the slope class and the direction of the slope produces the highest average annual increment of diameter in the flat slope class with the direction of the slope facing north, which is 1.79 m / year while the highest annual increment of the total average height is in the very steep slope class with to the slope facing to the north at 0.82 m / year.

Wheat Yield Responses to Rising Temperature: Insights from North Indian Plains of India

Climate change and consequent variations in temperature pose a significant challenge for sustaining wheat production systems globally. In this study, the potential impact of rising temperature on wheat yield in the north Indian plains, India's major wheat growing region, was analyzed using panel data from the year 1981 to 2009. This study deviates from the majority of the previous studies by including non-climatic factors in estimating the impact of climate change. Two temperature measures were used for fitting the function, viz., Growing Season Temperature (GST) and Terminal Stage Temperature (TST), to find out the differential impact of increased temperature at various growth stages. Analysis revealed that there was a significant rise in both GST as well as TST during the study period. The magnitude of the annual increment in TST was twice that of GST. Wheat yield growth in the region was driven primarily by increased input resources such as fertilizer application and technological development like improved varieties and management practices. Most importantly, the study found that the extent of yield reduction was more significant for an increase in temperature at terminal crop growth stages. The yield reduction due to unit increase in TST was estimated to be 2.26 % while rise in GST by 1◦C resulted in yield reduction of 2.03%.