Danum Valley Conservation Area
  Roman Dial   Sep 26, 2005 22:20 PDT 


Thanks for all the encouraging responses to the Borneo finds. It's
exciting to share them with such an enthusiastic audience.

I'll start with my narrow connection to the big tree world. My PhD work
was on canopy ecology of Caribbean anoles (little green lizards we
called chameleons when we were kids). That research was almost too long
ago to mention, but as a graduate student I shared my dream of extensive
horizontal canopy movement (one month without coming down -- like the
Baron in the Trees!) with George Koch, who was even then (early 90's)
working with Steve Sillett (the two and a grad student of Steve's
recently published a fascinating article in Nature on the limits of
redwood height).

I then met Sillett at a canopy conference in Florida and through Steve
met BVP during an expedition to Australia which I funded using a
National Geographic Grant back in 2002 (a "canopy trek" of 5 days,
moving tree-to-tree through the beautiful Wallaby Creek canopy in
Victoria). It was on that expedition that BVP introduced us to Brett
Mifsud of Australia and his tree climbing partner Tom Greenwood. It was
Brett who told BVP about Wallaby Creek.

Then, on a recent trip to Borneo I heard of a new conservation area
called Imbak Canyon Conservation Area in Sabah. Sillett and I had
visited the older and better known Danum Valley Conservation Area
together in 2002 and found (and climbed) several large trees, including
a 79.5 m Shorea gibbosa, a 75.0 m Koompassia excelsa, and a 72.8 m
Parashorea malaanonan. In fact we climbed all these at Danum in 2002:

79.5 Dipterocarpaceae Shorea gibbosa
75.0 Leguminosae          Koompassia excelsa
72.8 Dipterocarpaceae Parashorea malaanonan
66.0 Dipterocarpaceae Shorea leprosula
63.0 Dipterocarpaceae Shorea johorensis
61.9 Meliaceae                 Azadriachta excelsa
59.2 Dipterocarpaceae Parashorea tomentella
59.2 Dipterocarpaceae Shorea parvifolia
52.6 Anacardiaceae         Dracontomelon costatum
40.8 Leguminosae         Dialium indum
Rucker index: 63.0 m or 206.9 feet for an area of less than 5 ha.

We (Sillett and I) didn't find all the tallest individuals of all
species in the area -- we were actually just looking for a good canopy
trek spot. Indeed, all but the big S. gibbosa are in a ~150 m by ~50 m
sample plot (the gibbosa is about 0.25 km away). Basically, it appears
that in the tropics as elsewhere, when you're in the big trees, they're
all pretty big, and it just so happens that every tree in a small patch
seems to be a different species (not completely, but it's crazy the
diversity, really crazy).

Now I'm giving you these Danum numbers because they are published and
it's a bit of history leading up to the latest expedition, the one with
*very* tall hardwoods.

Roman