February 17, 2013
If you have called or emailed me recently, you have received an “out of office” message saying I would be away in February. The full story is that I am in the mountains of Northern Thailand, helping my graduate student, Hathai, with her dissertation research on forest regeneration dynamics of understory trees. Her work is part of a bigger effort at Chiang Mai University (CMU) to study how to restore diverse, seasonally-dry tropical forests.
Thailand has lost over half its forest areas in the last 40 years to unsustainable timber harvest practices and land use conversion. In the mountains of Northern Thailand, most forest loss and degradation is driven by a history of shifting agriculture. Abandoned after farming, much of this land becomes dominated by aggressive invasive perennial weeds which prevent forest regeneration both by directly competing with seedlings and also by feeding widespread fires each dry season (March-May). These fires are not part of the natural fire regime, but are human-origin fires that kill many of the young seedlings getting established naturally, or as part of planting efforts. This favors and perpetuates the weed communities rather than native forests.
The Forest Restoration Research Unit (FORRU) at CMU has been working on this restoration challenge for the past two decades. The FORRU team began their work with basic research on local forest trees, studying life cycles, flowering and fruiting phenology. Likewise, they tackled challenges in nursery production by testing germination and nursery cultural requirements to help them grow and plant viable seedlings. All very much as was done in the Oregon four or five decades ago.
Success in the field came by both controlling the weeds in the plantations for several years after planting (no surprise to us in Oregon) and very importantly, through rigorous and on-going community-level fire suppression.