In article <29mo7gINNbh1 at eccdb1.pms.ford.com>, goldstro at be0238.be.ford.com (Mitch S. Goldstrom) writes:
>I have a bet to settle with a colleauge, so I thought that I would
>consult the experts.
>>When driving by a cluster of trees in a convertable, the air temperature
>seem to drop a few degrees. I postulated that this was due to the trees
>giving of oxygen. He thinks I am crazy and gave me some nonsense about the
>pavement and big-city insults. Who is correct?
>>Thanks in advance,
>goldstro at be0238.be.ford.com
The upper canopy of tall forest trees intercepts more than half the radiant
energy of the sun. This percentage often drops to less than 10% by the time
you reach the forest floor. Wherever the shade from the trees was falling,
the ground would be absorbing/reradiating less heat- air circulating through
there would be cooler. If the shade was on the pavement, this effect would be
particularly noticable. I'm not sure where your O2 theory is coming from-
lower greenhouse gas concentration, maybe? Or less heat conductivity?
Anyway, you probably need a larger area and greater differentials to see such
RICHARD WINDER Title: Visiting Fellow
Forestry Canada Phone: (604) 363-0600
Victoria, B.C. Internet: RWINDER at A1.PFC.Forestry.CA