Growth of Shorea contorta Vid. Inoculated with Eucalypt Ectomycorrhizal Fungi in the Nursery and in a Logged-Over Dipterocarp Forest in Surigao, Philippines

Abstract

This study was conducted to determine the compatibility of ectomycorrhizal (ECM) fungi associated with eucalypts on dipterocarps. Two nodal cuttings of Shorea contorta (Vid.) were rooted in a non-mist system for two months, and later inoculated with vegetative mycelia of three strains of Pisolithus collected under eucalypts and a strain of Scleroderma from dipterocarps. Inoculated rooted cuttings were planted in irradiated potting mix and raised in the nursery for five months. Root colonization prior to outplanting ranged from 31% to 38% and ECM fungi did not colonize the uninoculated ones. The cuttings were outplanted in a logged-over dipterocarp forest in Bislig, Surigao Sur following a Randomized Complete Block Design with four blocks; each block was planted with 50 seedlings. Two years after outplanting, Pisolithus strain from New Caledonia (H6394) promoted the highest height (46 cm) and diameter (0.48 cm) increment. Height was increased by 17% and diameter by 7% relative to the uninoculated control. By contrast, Pisolithus strain from the Philippines (H615) gave the shortest (26 cm) height increment and smallest (0.42 cm) diameter. Diameter growth of cuttings inoculated with Scleroderma D01 (from the Philippines) and a Pisolithus strain from Australia (H445) was bigger (0.47 cm) than the uninoculated treated cuttings (0.45 cm). In terms of survival, the uninoculated cuttings gave the highest (90%) percent survival while the lowest (60%) was those inoculated with Pisolithus strain from New Caledonia. It is possible that the indigenous ECM fungi infected easily the roots of the uninoculated cuttings thus contributing to the high survival rate (90%). During outplanting, fruit bodies of S. columnare were present in the field site. The results, however, show that ECM fungi were able to colonize the roots and that some strains promoted the growth and survival of S. contorta planted in a logged-over dipterocarp forest in Bislig, Surigao, Philippines.