From J. K. JACKSON
In reply to John Brunner Letters, 8 June, whether a tree is coniferous
or broad-leaved is irrelevant to its effect on the carbon dioxide in the
atmosphere. Plants immobilise carbon dioxide by converting it into sugars,
starch, and the various constituents of wood; thus the plant which is quickest
growing will absorb carbon dioxide fastest. Plants release carbon dioxide
to the atmosphere when they decay, are eaten by animals, or are burnt. Thus
a long-lived tree with durable timber will retain carbon dioxide for a longer
period than a shorter-lived perishable plant. The ideal would be a tree
living many years with a high average rate of growth throughout its life.
In this country it might well be a conifer; perhaps in the tropics a species
of eucalyptus.
J. K. Jackson Pinner, Middlesex
