An ecological appraisal of Pinus roxburghii Sarg. (Chir pine) and Shorea robusta Gaertn. (Sal) plantations in Doon valley

The present study focused on phyto-sociological and physico-chemical attributes of soil in Pinus roxburghii (Chir pine) and Shorea robusta (Sal) plantations in a reserved estate of New Forest, Dehradun. A total of 33 plant species comprising of 18 trees, 10 shrubs and five herbs were recorded from the study area. The tree density, in chir pine was lower 950 individuals/ ha as compared to 1073 individuals/ ha in sal vegetation. In saplings, high density was observed for Syzygium cumini (20 individuals/ 100m2) in sal followed by Broussonetia papyrifera (19 individuals/100m2) in chir pine plantation. Lantana camara, marked its presence with highest density (49 individuals/100 m2) in chir pine followed by Clerodendrum infortunatum (18 individuals/100 m2) in sal plantation. Higher tree basal cover (51 m2/ha) was recorded in sal than chir pine (19 m2/ha). Similarly, the tree diversity in sal was recorded higher (1.68) as compared to chir pine (1.51) plantation. Contrarily, sapling diversity was higher (2.81) in chir pine as compared to sal (2.52) plantation. Herbaceous flora was completely absent in sal plantation. Analysis of size class distribution revealed that sal trees (~ 29%) attained 21-30 cm diameter whereas chir pine trees (68%) were under 11-20 cm diameter class mainly due to preferred growing zone of the species and habitat suitability. The soil under chir pine was slightly acidic (5.98) with sandy loam texture. Soil was comparatively good with higher soil organic carbon (2.71%) under sal plantation mainly due to high humus deposition. It is suggested to restrict wide spread of Lantana camara in chir pine plantation for the better growth of the species and enhance nutrient availability.