Diameter distribution model development of tropical hybrid Eucalyptus clonal plantations in Sumatera, Indonesia: A comparison of estimation methods

Background: Effective forest management and planning often requires information about the distribution of volume by size and product classes. Size-class models describe the diameter distribution and provide information by diameter class, such as the number of trees, basal area, and volume per unit of area. A successful diameter-distribution model requires high flexibility yet robust prediction of its parameters. To our knowledge, there are no studies regarding diameter distribution models for Eucalyptus hybrids in Indonesia. Therefore, the aim of this study was to compare different recovery methods for predicting parameters of the 3-parameter Weibull distribution for characterising diameter distributions of Eucalyptus hybrid clone plantations, on Sumatera Island of Indonesia. Methods: The parameter recovery approach was proposed to be compatible with stand-average growth and yield models developed based on the same data. Three approaches where compared: moment-based recovery, percentile-based prediction and hybrid methods. The ultimate goal was to recover Weibull parameters from future stand attributes, which were predicted from current stand attributes using regression models. Results: In this study, the moment method was found to give the overall lowest mean error-index and Kolmogorov– Smirnov (KS) statistic, followed by the hybrid and percentile methods. The moment-based method better fit long tails on both sides of the distribution and exhibited slightly greater flexibility in describing plots with larger variance than the other methods. Conclusions: The Weibull approach appeared relatively robust in determining diameter distributions of Eucalyptus hybrid clone plantation in Indonesia, yet some refinements may be necessary to characterize more complex distributions.

Performance of Tree Species on Waterlogged Sites of Canal Command Area: A Case Study of Bargi Dam, Jabalpur (Madhya Pradesh)

Bio-drainage is removal of excess soil water through bio-energy of fast-growing tree species having higher transpiration rate. Seven tree species viz. Albizia lebbek, Albizia procera, Acacia nilotica, Dalbergia sissoo, Eucalyptus tereticornis, FRI-4 and FRI-5 clones of Eucalyptus hybrid, Terminalia arjuna and Pongamia pinnata were evaluated for their performance through growth characteristics and biomass studies by planting on waterlogged sites on the bank of Left Bank Canal (LBC) of Bargi command area, Jabalpur district of Madhya Pradesh state (India). Eucalyptus hybrid, followed by Pongamia pinnata exhibited maximum height and biomass accumulation and its allocation to leaves and branches after four years of plantation,attributing the most desirable species for reclaiming waterlogged sites along canal command areas with similar edaphic and climatic conditions.

Tissue Proportion, Fibre, and Vessel Characteristics of Young Eucalyptus Hybrid Grown as Exotic Hardwood for Wood Utilization

This study sought to determine selected anatomical properties of young Eucalyptus hybrid species (E. grandis x E. urophylla) grown in Ghana. Images of fibres from macerated wood, and micro–sections produced with microtome were analysed using a compound digital microscope associated with Motic Image Plus Software (MIPS), version 2.0, installed on a computer. Images were initially processed using ImageJ software. Study data were analysed using an R statistical package. The overall mean value for fibre length was 907.67 µm, whereas double fibre wall thickness was 7.76 µm. Both variables had higher mean values in sapwood than in heartwood. Nevertheless, the found values decreased from the butt to the top portion. Statistically, axial and radial positions had no influence on fibre characteristics. In a 1 mm2 of the cross-section, the proportion of fibres was 38%, vessels were 19%, axial parenchyma were 22%, and radial parenchyma were 21% on average. Again, the radial and axial positions had no statistical influence on tissue proportion traits for the young eucalyptus wood. Mean value for vessel area was 9462.04 µm2 , whereas vessel frequency per mm2 was about 14. Vessels were significantly larger in area (range 9982.50 – 13544.41 µm2 ), yet reduced in frequency (range 6 – 17 per mm2 ) for sapwood. In heartwood, vessel area was comparatively smaller (range 6321.15 – 7816.69 µm2 ), whereas their frequency was high (range 15 – 18 vessels per mm2 ). Axial and radial position had statistical influence on vessel frequency and area for the young Eucalyptus grown in a plantation in Ghana.

Effect of short-rotation trees on nutrient dynamics and rooting pattern in intercropped with aromatic grasses in terai of U.P.

An Experiment was conducted in District Pilibhit.U.P., to study the yields of aromatic grasses in pure fields as well as intercrops under Populus deltoids and Eucalyptus hybrid. Quantity of litterfall, its chemical composition, nutrient addition, changes in chemical constituents of soil and herb and oil yield of Cymbopogon spp. were studied under agroforestry systems involving Populus deltoids and Eucalyptus hybrid with intercrop of Aromatic grasses (C.winterianus, C.martinii, C.flexouses). Trees were intercropped with grasses have significantly more diameter and height in comparison to trees planted without intercrops. High herbage and oil yield was recorded in pure fields of grasses than their crops intercropped with trees. Maximum yield was produced by Palmarosa and minimum by Citronella in poplar plantation intercropped. In Eucalyptus hybrid intercropped grasses, maximum oil yield was produced by Lemon grass and minimum by Palmarosa. Higher quantity of litter was produced in Palmarosa and lower was produced in Citronella intercropped trees. The litter produced by the intercropped stands had higher NPK contents than pure stands. The concentration of nutrients in the litter decreased with increasing age of the stands. Similarly, the total addition of nutrients (NPK) through litter fall to the soil increased as the age of trees increased. In the field of trees intercropped with Palmarosa was maximum addition of nutrients, while in Citronella intercropped field it was seen minimum. In comparison to intercropped stands, available NPK content of soil was higher in pure stands of trees. Maximum amount of N and K was found in superficial layer of the soil, which decreased with increasing depth. Most of the phosphorus was accumulated in the soil at the depth of 15-30cm in all the stands. The concentration of roots was more near the base of the trees at juvenile age,but as the age increases the roots tended to proliferates uniformly.. The total root biomass decreased continuously with increasing soil depth at all the radial distances and under all the age groups. It is clear that there is no completion among the root system with roots of intercrops grown along with Poplar and Eucalyptus.