Forest tree growth is linked to mycorrhizal fungal composition and function across Europe

Most trees form symbioses with ectomycorrhizal fungi (EMF) which influence access to growth-limiting soil resources. Mesocosm experiments repeatedly show that EMF species differentially affect plant development, yet whether these effects ripple up to influence the growth of entire forests remains unknown. Here we tested the effects of EMF composition and functional genes relative to variation in well-known drivers of tree growth by combining paired molecular EMF surveys with high-resolution forest inventory data across 15 European countries. We show that EMF composition was linked to a three-fold difference in tree growth rate even when controlling for the primary abiotic drivers of tree growth. Fast tree growth was associated with EMF communities harboring high inorganic but low organic nitrogen acquisition gene proportions and EMF which form contact versus medium-distance fringe exploration types. These findings suggest that EMF composition is a strong bio-indicator of underlying drivers of tree growth and/or that variation of forest EMF communities causes differences in tree growth. While it may be too early to assign causality or directionality, our study is one of the first to link fine-scale variation within a key component of the forest microbiome to ecosystem functioning at a continental scale.

Sifat kayu jati unggul nusantara (Tectona grandis L.f.) pada tiga kelas diameter pohon

Increasing the growth rate of teak trees is carried out to shorten the tree harvest rotation and reduce the deficit of teak timber supply, while maintaining the superiority of wood properties. The study was conducted to study the nature offive-year-oldJUNTeak wood in three classes of tree diameter and radial position of the trunk.This study employed a completely randomized design arranged in factorial combinations of the treatments of radial positions and diameter classes consisting of large (18-22 cm), medium (14-18 cm) and small (10-14 cm) stem diameters, andthe radial position of wood on the trunk based on the tree's ring. Three samplesof trees werefelled for each stem diameter classso that totally nine trees were used in this study. The testing of the physical properties of wood and the measurement of fiber dimensions were conducted using British Standards 373 and the IAWA method, respectively. The results showed that the diameter of the tree and the radial position of the wood had a significant effect on all parameters observed (fiber dimension and physical properties of wood), except the fiber diameter. The tree growth rate had a negative correlation with fiber length (-0.67), fiber wall thickness (-0.65), air-dry moisture content (-0.91) and air dry specific gravity (-0.86), and had a positive correlation with fiber diameter (0.61) and greenwater content (0.78). According to the pattern of wood properties in the radial direction, JUN wood harvested at the age of five was categorized as juvenile wood.This wood is acceptable as furniture and lightweight construction material.

Wood Anatomical Features and Physical Properties of Fast Growing Red Meranti from Line Planting at Natural Forest of Central Kalimantan

High productivity fast growing species plantation establishment such as the line planting of red meranti (i.e Shorealeprosula and Shorea parvifolia) with intensive silviculture is one potential solution to improve wood supply for industries in Indonesia. However, the information of anatomical properties and wood properties of these two species related to the influence of the line planting system and tree growth rate is limited. This paper studies the anatomical features, wood cell proportions, fiber dimensions and physical properties of wood in radial variation in relation to the line planting effect and tree growth rate. Wood of the trees grown in the line planting system showed higher proportion of vessel element compared to those of wood from natural forest. The vessel diameter of wood from the line planting was also larger than that of in wood from natural forest. The specific gravity of wood from Shorea parvifolia grown on the line planting was higher than that of wood grown in natural forest. The variation of specific gravity on wood portion near to the pith of Shorea leprosula and Shorea parvifolia trees grown on the line planting was related to the variation of the cell wall thickness. The bigger diameter of trees grown or the faster growth rate in the line of planting at the same age shows the greater vessel diameter in wood of Shorea leprosula and Shorea parvifolia and greater specific gravity of Shorea parvifolia wood.

Effect of Alumina and Halloysite clay on Electrical tree growth in Silicone Rubber Nanocomposite

Nowadays Silicone Rubber (SiR) is recommended in high voltage cable accessories fabrication as it offers excellent electrical and mechanical properties. Electrical tree is one of the phenomenon which contributes to the main factor of SiR insulation breakdown. Recently, a new approach has been applied in order to enhance the insulation strength properties by introducing nano filler in undoped material. Thus, this paper presents the influence of nano-alumina and halloysite nanoclay on electrical tree growth in SiR at 0, 1 vol%, 2 vol% and 3 vol% concentration. The electrical tree growth was investigated at 8kVrms after tree inception voltage (TIV) within 30 minutes under room temperature. The results show reductions of electrical tree growth speed and accumulate damage (%) up to 2 vol% nano-alumina and up to 3 vol% halloysite nanoclay. Nevertheless the presence of 3 vol% nano-alumina in SiR leads to the faster electrical tree growth rate and the worst accumulate damage within 1 minute of electrical tree growth process.