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The UP Arboretum

Proto credit: Dr. Gil Jacinto

The UP Arboretum has variably been the subject of scientific study, illegal settlement, green advocacy and University custodianship. Measuring a mere sixteen hectares of the 493-hectare academic institution that is the Diliman campus of the University of the Philippines, it supports a diverse collection of plants and wildlife, which, while not necessarily remarkable as compared to undisturbed ecosystems, can still be considered a compelling attempt at environmental preservation in the face of urban accretion and human threat.


Although dubbed as the remaining rain forest in Quezon City, the site of the UP Arboretum in the northern portion of the UP Diliman campus was not initially a dense forest. About the time of the inception of UP Diliman in 1939 from a land donation of the Tuazons and as an extension of the first campus located in Manila, the zoning of that portion of the campus was for parks, athletic and open spaces. It was also considered in a site development study as the location of a university town. The site was, in actuality, open land when it was part of the Tuazon Estate.

The advent of the Second World War, however, halted the implementation of any sort of development plan.  the Japanese Army occupied the few existing buildings of the campus at the height of their occupation of the country. Upon the withdrawal of the Japanese at the end of the war, the campus site was used by the Armed Forces of the Western Pacific (AFWESPAC) of the United States Army, where their improvements – the quonset huts, mess halls, residences and barracks – were turned over to the University in lieu of rent. The location where the Arboretum stands now was designated, in a survey done in 1947, as a wooded area with American Employees’ Quarters.

In 1948, following the turnover of the campus by the Americans to the University, The UP Arboretum was established under the Reforestation Administration (RA) of the now defunct Department of Agriculture and Natural Resources (DANR) to serve as a nursery in the forestation activities of the RA in nearby localities. Trees were planted to modify the micro-environmental conditions of the nursery, as it was originally a grassland containing a few fruit-bearing trees such as mango and tamarind. The administrative jurisdiction of the nursery was officially transferred from the RA to UP Diliman on August 15, 1962. Its operation has then expanded from a nursery to a repository of endangered, endemic and exotic plant species, which after some time successfully evolved into a man-made forest (Sotalbo, 1986).

Protecting the UP Arboretum: A Welcome Challenge

Like the rest of the undeveloped portions of the UP Diliman campus, the UP Arboretum is under constant threat. In 1957, the construction of Commonwealth Avenue reduced the northern portion of the campus to one-third its original size. By the 1960s, despite the infusion of funds from the Rockerfeller Foundation for the formulation of a comprehensive development plan for the UP Diliman campus, wherein the formation of a series of green areas, starting from the huge quadrangle of the Quezon Park west of the campus all the way to the Marikina Valley just off the Balara Filtration Plant, reached its height, the construction of large structures and complexes around the UP Arboretum also took place, which include the Philippine Nuclear Research Institute, the National Hydraulic Research Center, the Philippine National Oil Company, the Philippine Social Science Center and the Asian Institute of Tourism. Parallel to the construction of these legitimate institutions was the slow influx of informal settlements, which have also consistently increased in the area, developing into distinct communities.

Numerous though the threats may be, keeping these in check is a welcome challenge for the University, since the UP Arboretum, despite being man-made, is home to a variety of plant and animal species. In a study conducted in 2001 by Emil Sotalbo, who once served as the Director of the Campus Maintenance Office of UP Diliman, the UP Arboretum was found to be home to 77 out of 192 plant species in the University, comprising 9,298 plants of the total 38,569 on-campus, the most in any major grid of UP Diliman. The more common tree species within the UP Arboretum are alibangbang, mahogany, palo-santo, monkey pod and tagutagu. This concentration of plantlife in the UP Arboretum may be largely due to the topographical features of the area. The elevation of the Quezon City plateau averages around 70 meters above sea level (Dizon, 1952). This elevation creates a westward slope. (Teves and Gonzales, 1950) This slope contributes to the adequate drainage of the soil, provided via small intermittent creeks flowing southwestward (Lim and Medalla, 2001). A ridge runs lengthwise along a southeast to northwest axis through the property with noticeably lower elevations on both edges, making for a discernable isthmus of greens. (Galingan etal, u.d.)

The plantlife of the UP Arboretum serves as the habitat for a variety of amphibians, reptiles, birds and small mammals, making for an interesting mix of wildlife in the area. In a survey conducted in 1998, a large variety of vertebrates were found: fifteen species of reptiles and amphibians on-campus, including Gekko gecko,thecommon house gecko (H. frenatus), Stejnegers’s hemidactylid gecko (H. stejnegeri), Hemidactylus sp., Mabuya mutifascia, Bufo marinus,  R. erythraea, R. magna, H. rugulosus, P. leucomystax and O. laevis in the UP Arboretum; forty-seven species of birds, including the Eurasian Tree Sparrow (introduced), Brown Shrike (winter visitor), Mountain Shrike (Philippine endemic), Long-tailed Shrike (resident breeder), Pacific Swallow (resident breeder), Yellow-vented Bulbul (resident breeder), Pied Fantail (resident breeder), Tailorbird, Lemon-throated Leaf-warbler (endemic) and the Spotted Dove (resident breeder) identified at the UP Arboretum; and a number of mammals, including C. brachyotis, P. Jagori or the fruit bat (endemic), R. amplexicaudatus, E. spelaea, S. murinus, Rattus norvegicus and Rattus exulans. The same study revealed that in comparing with historical records of the assemblage of bird species in the UP Diliman area and its environs, six species of birds that used to be found in the study sites are now no longer present.

Protecting the UP Arboretum has compelled the UP Administration to designate it as a Priority Protection Zone. Formulated by the UP Diliman Development and Planning Committee in 2003, the policy stipulates that the UP Arboretum “...shall not be subject to any invasive development or other activities that will undermine its environmental integrity.” In the 2012 Land Use Plan of UP Diliman, the UP Arboretum is designated as a Protected Forest Area which ”...shall remain untouched and protected in accordance with law. In relation to use by the faculty, students and staff of UP Diliman, it shall be for academic purposes with minimum or no negative intervention.”—MAA


2012 Land Use Plan of UP Diliman. Approved by the Board of Regents on 27 January 2012 at its 1277th Meeting.

Abadingo, M., Calleja, J.M., Lumang, M.R., Mina, M. & Nono, K. (2002). Vegetation Survey and Road Map Update of the UP Arboretum. Ekolohiya. 1 (1)

Araneta, M.A. (2008). The University Of The Philippines In Diliman and Its Peripheral Area: Aspects Of The University Experience From The Viewpoint Of UP Users. UP School of Urban and Regional Planning (master’s thesis)

Galingan, Z.C., Flor, E.G. & Chun, A. (u.d.) The National Botanic Gardens: Creating an Urban Oasis within the University of the Philippines

Lico, G.R., Araneta, M.A., Manalang, R.T., Jose, R.T., Flores, P.D. & Galingan, Z.D. (2008). Designing Diliman: Campus Architecture, and the Designed Environment of the University of the Philippines: 1939-2008. National Commission for Culture and the Arts (Exhibit Material)

Office of the Campus Architect. (2005). Development and Planning Policies for UP Diliman. University of the Philippines Diliman (unpublished manual). Diliman, Quezon City: Author.

Ong, P.S., Pedregosa, M.dG. & de Guia, M.G. (1999). Wildlife Inventory of the University of the Philippines Diliman and the Ateneo de Manila University Campus, Diliman, Quezon City, Luzon, Philippines. Science Diliman (January – June 1999) 11(1), 6-20

School of Urban and Regional Planning . (1996). Development Options for the U.P. Diliman Campus. Diliman, Quezon City: Author.