35 Journal of Environmental Science and Management 25-2: 35-50 (December 2022) ISSN 0119-1144 Kathreena G. Engay-Gutierrez 1* Eraldwin A. Dimailig 1 Jenny M. Yacon 2 1 Forestry and Environmental Science Department, College of Agriculture, Southern Luzon State University, Lucban, Quezon, Philippines 2 Department of Environment and Natural Resources- Environmental Management Bureau CALABARZON, Roxas Boulevard, Ermita, Manila, Philippines * corresponding author: kathreenaegutierrez@gmail.com ABSTRACT The selection of forest trees as planting materials in reforestation projects or plantation development could be based on the existing needs of the wood-based industry, and in support of the National Greening Program. It is anchored on natural adaptation to ensure high survival rates considering suitability to prevailing site conditions; purpose for planting; availability of planting stocks; and commercial value. Thus, selection and mapping of plus and mother trees at the northeastern slope of Mt. Banahaw de Lucban, Philippines were conducted to determine potential seed production areas as sources of quality planting materials. Information materials were developed for dissemination. Twenty-two species with 65 individuals representing families of Annonaceae, Fabaceae, Fagaceae, Clusiaceae, Meliaceae, Myrtaceae, Podocarpaceae, Sapindaceae, Sapotaceae, Symplocaceae, Theaceae and Tiliaceae showed vigorous growth and superiority in height and diameter compared with the surrounding trees. Phenotypic characteristics are influenced by temperature, rainfall, soil and elevation. Highest population of plus trees was distributed in moderate to steep slope. Favorable soils for growth were found at lower elevations. Species diversity of 2.00 showed moderately diverse plus trees at 700 masl and 800 masl. However, 11 species were found threatened as listed on DENR Administrative Order (DAO) No. 11, s. 2017 and the International Union for Conservation of Nature (IUCN). Keywords: selection, mapping, plus trees, quality planting materials, phenotypic INTRODUCTION The production of quality planting materials through clonal nurseries and vegetative propagation techniques are essential in the implementation of the National Greening Program (NGP) in the Philippines. Thus, the government through the Department of Environment and Natural Resources (DENR) promotes the use of high-quality planting materials in the establishment of tree plantations and other forestation activities (DENR Administrative Order [DAO] No. 2010-11). The expansion of NGP (Executive Order No. 193. s. 2015) aims to recover all the remaining unproductive, denuded, and degraded forest for the period 2016-2028. The production of quality planting materials is a priority. The selection and characterization of forest tree species must be anchored on natural adaptation to ensure high survival rates.. The following factors should be considered: suitability to prevailing site conditions, purpose for which they are planted, availability of indigenous planting materials, and commercial value based on the existing needs of the wood-based industry in the region, and in support to the NGP. However, the main factors shaping-up JESAM Plus and Mother Trees in Mt. Banahaw de Lucban, Quezon, Philippines quality planting materials of timber species are based on physical and genetic characteristics. The observable characteristics of tree species with the interaction of genotype to the environment make up its phenotypic characteristics. Thus, plus trees possess better or superior phenotypic characteristics compared with other trees of the same species grown under the same environment. A plus tree is selected from other trees for its outstanding and above-average growth, form, wood quality, and other desired characteristics that appear adaptable to the environment but have not been tested for genetic worth. Mt. Banahaw de Lucban, a protected landscape under Republic Act 9847 of 2009 has extremities in elevation within it allowing the formation of a wide range of habitats supporting high diversity and endemicity of flora and fauna (Samaniego 2016). Forest trees in Mt. Banahaw de Lucban are candidate trees for identification, selection, and characterization for plus or mother trees. Plus trees are candidate trees with fair to good phenotypic characteristics with the potential to provide good quality seedlings/wildlings in the future