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Siit Arboretum’s ideas on sustainability

Volume 6 Number 2 - July 2009

Eric Hanquinet


Sustainability issues for the Siit Arboretum in the Philippines have been a regular focus of our projects. Simply said, we cannot afford not to be sustainable in what we do, as our income is very limited. When we do spend some hard earned income, or gratefully receive some grants, it is an extra reward to deliver the outputs in a sustainable way. Here are some examples which might serve other gardens in the same situation:

Building and construction

In the budget for construction, roof support/structure framing is a serious consideration. The cheapest materials for covering for us, as in most places, are at the present time "galvanum", a light type of corrugated steel sheet with good sun reflection, which normally demands welded steel framing or lumber. We have found that bamboos, which we have in large quantities, can provide an excellent replacement for standard roofing supports and can even accommodate insulation foam with good aesthetic results. Light, strong and flexible, bamboos are long lasting when not exposed to the rain. All our buildings have been framed this way for many years, with no sign of any problems. We have saved money and many trees using this process. Bamboos also are used with palms fronds for shed extensions along the building where an eventual water leak is not a major problem.

Sharing costs with the community

The Siit Arboretum recently received a grant from BGCI, permitting the construction of a library and the installation of an internet connection, the latter needing a costly antenna of great height. However, through the extra investment of a good quality secondary router for WI-FI delivery, the garden is able to share its internet access with the surrounding neighborhood and, through network participation rent, does not need to spend anything for the actual server yearly fees.

Use of solar power

Siit Arboretum’s water delivery and irrigation system works entirely on solar power, with new technology providing controllers, electronic boosting and rearranging the voltage/amp ratio for optimal rating. We therefore have no need for batteries and yet have a good daily delivery with a limited number of solar panels.


Siit exported this technology to Siquijor Island at the request of their Department of Agriculture representatives after a visit to the garden. This island had been entirely dependent on fossil fuels, but two solar pumps are now helping a local community and a good size organic garden produce high quality crops. Two more pumps have been organized by the Arboretum at the request of the Governor who is extremely impressed by the savings generated by the system.

The Arboretum provides a good platform to advertise alternative energy and other issues linked to global warming. In the process, a commission on purchases is gladly paid by the recipients for whom we arrange the logistics in procuring the right equipment, and this helps the garden financially.

Medicinal plants

The value of our plant world can hardly be better illustrated than through its medicinal assets. Siit Arboretum now displays a herbal garden including many useful native species and manufactures some basic herbal medicines. Particularly praised are our fresh products of Pau d'arco, Tabebuia impetiginosa, “Lapacho”, which grows happily here, and delivers excellent anti bacterial and anti viral properties. Various uses are also made of the locally grown Moringa oleifera, a highly nutritious plant and Centella asiatica, a weed rarely noticed around here but rich in health benefits including skin rejuvenation, and memory enhancement. As the Arboretum is situated on clean land with no neighboring farmers using pesticides, the production of organic medicinal products seems a good prospect for this area.

Essential microorganisms

Recent price rises have made the purchase of fertilizers impossible for many farmers, and many are now decreasing (or stopping all together) their planting of corn and other crops. This is largely due to years of monoculture and soil mismanagement which has depleted their soils of fertility. The Arboretum is now working at demo- manufacturing several types of organic fertilizers using essential microorganism cocktails of various sorts. These are based on easily sourced raw materials and locally available waste products (e.g. copra meal, rice bran, Leucaena cuttings). Molasses, the main ingredient to promote fermentation is very cheap in a sugarcane growing area, and many good recyclable waste products are available locally. Some efficient microorganisms are being now manufactured by the Department of Agriculture, working with local NGOs. Botanic gardens are well placed not only to spread awareness of this technology through demonstrations, but also to benefit from using such methods themselves for sustainable production systems.

Solar ovens

Another part of our display is an ‘easy to make’ solar oven. Solar cooking is not common in the Philippines and much time is spent in gathering wood everyday and of course cutting trees. However, sun is the one asset that the Philippines islands have never been short of and solar cookers can comfortably provide at least 50 % of a family’s cooking needs. This technology is also used to produce some of our medicinal plant extracts.


Siit Arboretum still has some way to go before the basic task is accomplished - that is: sustaining itself! However taking into account the above, and adding a few ornamentals sales, seeds sales, further organic ideas, and may be after all, a botanical garden could survive without a significant income from its visitors.

For more information, visit and click on the weblog link for more details of our activities.

Eric Haniquet
Siit Arboretum Botanical Garden
c/o Park avenue hotel
Perdices St.
Negros Oriental 6200