Conservation of the Dipterocarps is  absolutely essential as these trees are the key component of these bio-diverse regions. Providing a complex forest environment with numerous levels of vertical diversity throughout the canopy. 
Logging and land conversion in South East Asia is occurring at such an alarming rate which exceeds the reproductive biology of the dipterocarps. 
  • It takes 80+ years for a dipterocarp to be re-productively mature.
  • Frequency of masting events is between 5 and 10 years.
  • Seeds do not survive in the soil seed bank, only as seedlings and saplings.
  • Logging and land conversion destroys the seedling and sapling bank.
Consequently the loss of dipterocarp species is alarming when one considers the geographical range of this species and the diversity of this species, which is enormous even in a very small land area.
  • In 2007 my students and I carried out a survey of mature dipterocarps in a 50m by 50m plot in a section of primary forest at Danum valley.
    • With the expert help of Mike Bernadus an outstanding research assistant at Danum.
  • ​Our findings were alarming, in our plot we recorded 17 mature dipterocarps, 13 of which are IUCN listed as under threat. 
Conservation of dipterocarps and indeed many tropical trees is challenging compared to conserving tree species from temperate zones like the UK. This is because many tropical plants, including trees and the dipterocarps are known as recalcitrant species. This means that the seeds can not be stored in a seed bank like the millennium seed bank at Kew Gardens, Wakehust Place.

​Therefore the dipterocarps require a different approach and here scientist have developed a seedling nursery. This is where seeds are collected after a masting event or where conservation workers collect young wildlings form the forest, this negates the need to wait for the seed rain. The seedlings are  then grown on in modified soil under shade tunnels. 
  • Dipterocarp seedlings have a very slow rate of growth and can be maintained in collections under shade for many years.
  • This mimics what naturally occurs in the forest as dipterocarps survive as young trees (about 1.2m to 1.4m high) in the understory. 
  • The amended soil is comprised of forest top soil and river sand to aid drainage. 
  • The forest top soil will help the establishment of seedlings as this soil is quite likely to contain propagules of ectomycorrhiza (EcM).
  • Ectomycorrhiza are naturally occurring soil dwelling fungi that form an association with plant roots. The evolution of EcM is ancient and dates back over 400 million years. (Burchett, S and Burchett, S., 2016).
  • EcM establish a fungal sheath around roots of plants which aids the uptake of nutrients and water and consequently enhances seedling establishment.
  • Seedlings are held in these shade tunnels until they can be replanted in the forest, often they can survive 10 years in the shade tunnels.
  • An excellent example of this approach is the FACE nursery at Danum valley, Sabah.
  • This nursery holds about 30 different dipterocarp species, which is a great step towards conserving the dipterocarps. However, one has to keep in mind there are over 280 species of dipterocarps in Sabah alone.
  • Selection of species for conservation has been done via applying a set of criteria, which includes ease of nursery management. This is because many dipterocarps are very difficult to manage in a nursery environment, this criteria then results in a narrow range of species conserved. 
​
Top two pictures illustrate amended soil in poly-liners, the next four pictures illustrate the range of shade tunnels, the next three pictures illustrate germinating dipterocarp seedlings in the forest understory, 2010. The next three pictures illustrate a range of dipterocarp seeds, the last two show emerging radicle. Next picture is a Samba deer, this is one of the many herbivores that graze dipterocarp seeds. The
​ final picture illustrates an EcM fungal sheath.
Conservation of dipterocarp forests is multifaceted and requires the implementation of reduced impact logging supplemented with enrichment planting of a range of dipterocarp saplings from the seedling and sapling nurseries. 
  • Reduced impact logging is a modified harvesting process that requires loggers to enumerate their cutting area, map extraction routes, label mother trees and other trees to be conserved. 
  • This process results in a reduced logging foot print on the harvested coupe, leaving a scattered matrix of mature and semi-mature trees and less soil damage due to the mapping of extraction routes. 
  • The advantage of this method is a remnant coupe that is capable of self regeneration from the remaining mother trees and the surrounding forest. 
  • This natural regeneration process can be augmented with the application of enrichment planting. 
Enrichment planting is a process where the seedlings and saplings are planted out in either lines or squares into the logged out coupe. The process takes a lot of ground preparation and requires constant management over at least a ten year period. 
  • The enrichment process is expensive and is often paid for under carbon mitigation protocols established under the Kyoto agreement.
  • The two schematics below illustrate the process of enrichment planting.
Top schematic illustrates a logged coupe before enrichment planting, similar structure to the photograph on the right. The lower schematic illustrates the process of enrichment planting.
Top two pictures illustrate a very degraded forest coupe following clear fell logging practice of the 1970s and 1980s. The next two pictures illustrate the results of reduced impact logging, note the more complex canopy structure compared to the degraded coupes. The next two pictures illustrate further recovery from logging and the sapling bank. The next picture illustrates the regional conservation effort in Danum valley, with sign posts to the FACE nursery. The final picture illustrates enrichment planting, the sapling with the yellow tape on the stem. The arm in the far right belongs to Dr Glen Reynolds. 
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