Pest and disease incidence of coniferous species in Taman Saujana Hijau,Putrajaya urban park,Malaysia

Taman Saujana Hijau(TSH),Putrajaya is a 41-ha urban park planted with various coniferous species from around the world.Insect pests and disease incidences of this park are unknown and there is a need for an evaluation of the health status of this urban park.This study assessed the level of pest and disease incidents of coniferous species in 12 plots of 7 species(Araucaria bidwilii,Araucaria haterophylla,Araucaria cunninghamii,Pinus caribaea,Pinus merkusii,Podocarpus polystachyus,and Podocarpus costalis).Termites,canker disease,and foliar disease are three major problems.The highest pest and disease incidence(PnDI)was foliar disease with a 0.49 coefficient correlation between the total number of trees and the PnDI,followed by canker disease with 0.40,and termites with 0.36.Of the seven conifers,A.haterophylla was the most infected followed by A.bidwilii and A.cunninghamii.It was concluded that the incidence of pests and diseases in TSH was moderate.To our knowledge,this may be the first baseline inventory of pests and diseases of coniferous species in Malaysia.

Temporal heterogeneity in climatic responses of four tree species in the Altai Mountains, northwest China

In the context of ongoing climate change,rela-tionships between tree growth and climate present uncertain-ties,which limits the predictions of future forest dynamics.Northwest China is a region undergoing notable warming and increased precipitation;how forests in this region will respond to climate change has not been fully understood.We used dendrochronological methods to examine the rela-tionship between climate and the radial growth of four tree species in a riparian forest habitat in Altai region:European aspen(Populus tremula),bitter poplar(Populus laurifolia),Swedish birch(Betula pendula),and Siberian spruce(Picea obovata).The results reveal that European aspen was insen-sitive to climate changes.In contrast,bitter poplar showed a positive response to elevated temperatures and negative to increased moisture during the growing season.Swedish birch and Siberian spruce were adversely affected by higher temperatures but benefited from increased precipitation.A moving correlation analysis suggested that,against a back-drop of continuous warming,growth patterns of these spe-cies will diverge:European aspen will require close moni-toring,bitter poplar may likely to show accelerated growth,and the growth of Swedish birch and Siberian spruce may be inhibited,leading to a decline.These findings offer insight into the future dynamics of riparian forests under changing climate.

Population structure,age and growth rates of conifer species and their relation to environmental variables at Malam Jabba,Swat District,Pakistan

This study focuses on age,growth rate and diameter distribution of pine forests in the Malam Jabba area,Swat District,Pakistan.Wood core samples were taken from twenty stands.Picea smithiana was the oldest at 234 years with a 112-cm diameter.Abies pindrow was 125 years with an 80-cm diameter while the oldest Pinus wallichiana was 122 years with 75-cm diameter.The fastest overall growth rate of 1.5±0.1 year/cm was for P.wallichiana on a west-facing aspect,while the slowest 5.8±2.6 year/cm growth was P.smithiana on an eastfacing exposure.P.wallichiana and A.pindrow exhibited marked differences in growth rates over a 5-year period.The highest growth was by P.wallichiana from 1966 to 2006.A.pindrow showed less growth over the same years,such pattern simultaneously reverse from 1911 to 1965.The relationship between diameter and age,diameter and growth rate and age and growth rate were correlated.P.wallichiana and A.pindrow ages were correlated with diameter and growth rates.P.smithiana age was positive correlated with diameter.Generally,topographic and edaphic factors did not show significant correlations with growth rates,although some appreciable correlations were recorded.The growth of P.wallichiana was correlated with elevation while A.pindrow was correlated with maximum water retaining capacity.Diameter and age produced uneven size classes and many size gaps,which could be the result of anthropogenic disturbances.