[College of ACES] [University of Illinois] [Illinois CES]

Re: What determines the growth rate of a tree? Part 2

jdunster@bigfoot.com
Fri, 6 Feb 1998 20:38:21 -0600

Yes, folks have been trying to speed up growth rates for many years and geneticists have been breeding the so called "super trees" for quite a while. Growth rate is partly a reflection of environmental conditions, and partly genetics. There are for example hybrid poplars that grow at fantastic rates; one can sit down and almost watch them sprout up. 5 to 6 feet a year is common, but the overall wood quality is poor. Similarly, there is much literature on the affects of improving environmental conditions and the increased growth rates resulting. But, merely by improving growth conditions it does not follow that there is an infinite increase in growth rates. All biological organisms have limiting factors, and all reach a plateau beyond which it is difficult to proceed further.

Each tree species has its own inherent growth rate and growth requirements such as ph, moisture, shade, rooting needs and so on. All of these can be "improved" to offer the maximum possible opportunity for development. But, always, there are limits. Generally, in my opinion, it is better to work with what nature provided and ensure that the natural species indigenous to an area have good growing conditions. It has taken many centuries, well eons acrtually, for natural selection proceses to determine optimum requirements for each species. That is, if you were a tree growing in the wrong place at the wrong time, you became extinct. If you need more information look in the forestry literature. It is widely predicted that global warming will create drastic shifts in species tolerances around the world. Certain tree species in alpine areas may dissapear, others will invade. Historically, we know that there have been major climatic shifts, whcih is why we can find perfectly preserved tropic
al forests, with wood,
leaves and cones all quite usable, buried in the high Canadian Arctic. The same species still exist in the tropics where conditions are still suitable. Overall, then I think it is better to work with what we have. Keep humanity in perspective as well; we are but a temporary glitch in planetary evolution!

Julian Dunster
Bowen Island, BC
Canada