OF INTEREST TO NATURALISTS.

Digger (Invercargill RSA), Issue 24, 27 August 1920, Page 8

OF INTEREST TO NATURALISTS.

LONGEVITY 0F TEERS. Trees attain a , great and -indefinite are. They are the longest-lived organismS of the vegetable kingdom, and greatly eXCeed the age of animals. There is no limit' such as that imposed hy individual decay in animal organisms to the age they niay attain Although it is seldom possihle to state with confidence the eiacf ngC of trees famed for length of days, there can be no doubt as to the enormtms antiquity of ma-ny of our trees, the \^s of our own country and the iaxned oaks and yews of Englaad. The setfioii oi a Yrunk of one of the maiurooUi hM3 0j California Sequoia gigantea fexled is 1890 ehows 1335 concent-ric rings deno!in» successive years of growth. It is jei. : rally acsumed that each year a tree ptoduces a single ring, althouglx a cafalali® on this assumption cannot be regardsdas j more than an approximation to the truth. As spring succeeds winter, the inaetivity of t-he plant machine is followed by a period of energ'etic life ; openi!i» of bnds and elongating shoots create a demand lor a plentiful supply of ae-cending sap, and in response tc this the tree produces a fresh cylinder of wood composed of relatively wicle condncting tubes. After the first rush of life is succeeded by n phase of more uniform and gentler activity, the demand fox* water become less, and the wocd formed during the rest oi the season

consxsts of narrower sap tuoe/j. Tne slteration cf lai-ger and smaJier tabes pto- ; duces the appearance of conrentric rinp on the cross sect-ion of a. tree. It is not the pause in the active life of the plant which is reeponsibJe for the effect of rinji, but the fact that the wood produced immediately before and after the pause is not structurallv identical. In trees grown under the more uniform conditions of certain trop'ical region s the annual rings are either feebly developed or absent, lor j example, in some India-n oaks the wood shows no rings cf growtli. The Sequoia gigantea is probably the largesf knom tree, oxxe has been measured 400ft. h'.ph, I with a trunk 116ft in cxrcumieYcw*. The Kauri Auskalis, the finesfc ahd best known New Zealand tree usuc-.lly r.vnges from 30 to 100ft. high with a trunk 4 to 10ft. diameter, but attaining an cstreme height of 150ft. with a trunk l&-22ft dxa. meter. The Wmfarihing oak cakcd the Old Oak in the time of Wiliiam the 0®queror 1066, is 40ft. in diMietfi JK1 1S believed to be 1600 years old, also the Kings Oak at Windsor forest, 26ft. circumference and the Shelton Oak 2oft. c> cumfer-iiice. The sxze of the gest of the famous Cedars of ' l'ange from 18 to 47ft in girth and u 80ft. high. The degree of aocuracy to allowed. to estimates of , age fonnde ^ the number of annual rings is of -e( ^ axy importance in compaiison wi i enormously greater bold on ufe f0by trees as contx*asted with the >8^ animals. T"ees are constructed on a P j fimdamentally differe.it from that i ing the structure of the highly humaa organism, and are thus f" with a set of potential i-"1 — V eronica.