THE DEADLY BORER.

Press, Volume L, Issue 14976, 25 May 1914, Page 3

THE DEADLY BORER.

RAVAGES ON N_W ZEALAND « TIMBERS.

INTERESTING EXHIBIT AT THE MUSEUM.

There is in the Canterbury Museum a very fine collection of the various timbers and woods furnished by the native forests of Now Zealand. Some of these specimens havo been in the Museum since the year 1867,. and have come from patches of forest which have long since disappeared. From tho nearness of the institution to Banks Peninsula it was reasonable that a'large proportion of the specimeus should come from that locality, and it is therefore found that Little River often appears as tho source of tho specimen, but it is surprising how many have come from the patch of bush which formerly existed in one of tbo gullies on the north side of the Port HilLs, once known as the Dry Bush. The collection also includes material from Deans's Bush, and from the forests of the West Coast and the North Island. A little time ago it was withdrawn from exhibition in order to make room for other exhibits, but a place has now been provided for it, and it is intended to restore it to view. In overhauling tho specimens it was found that a largo number had been attacked by tho borer, and the • following facts with regard to the behaviour of tho different woods are supplied, a-? they may bo of interest to the general public, aud especially that section of it which takes an interest in our timbers.

Tho specimens havo all been exposed to the attack of the borer for many years since adjacent portions of the building wero completely riddled, and have had to be replaced "quite recently. It is not, however, asserted that the results afforded by this collection aro entirely satisfactory, especially as the susceptibility of wood to attack depends in some measure on the conditions under which tho timber is grown, the time of year at whicli it is cut, as well as on the properties peculiar to the timber itself. A few years ago Professor Kirk, of Wellington, published two short papers showing that the attacks of the borer depended to some extent on the amount of starch and glucose contained in tho timber, that timbers containing these substances were more susceptible, and that the amount present depended on the time at which the timber was cut, and on the possibility of the glucose being dissolved out owing to exposure to water. It is not known whether Professor Kirk has continued his researches, but the matter has an economic interest, perhaps not as regards the behaviour of our fast disappearing native timbers, but as regards the imported and locally grown, non-native woods, which-are, no donbt, variously susceptible to the inroads of this pest. The collection in the Museum includes woods capable of being used for building or larger constructional purposes, as well as those which, from their small size are only suitable for cabinet work.

Of the former the following show no sign of damage: kauri, miro, puriri, maire, manuka, kowhai. rata, pohutukawa. towai, the native honeysuckle, mahoe, and the mountain beech. The following are only slightly damaged, some specimens being unharmed: totara, hinau, broadleaf. while the following timbers have suffered badly: black and white birch, black pine, the rimu, tawa, cedar (kawhaka). and Jthe yellow silver pine. Of three specimens of white pine (kahikatea) two aro unharmed, while tho third is only s'-ghtly affected. Of those woods of smaller size and used for cabinet and inlaid work, the following show no sign of harm: the pepper wood, titoki, mahoe,' the myrtle or" various species,

koromiko. ribbonwood, g-r_**s tree, -*-ild I Irishman; and of twelve samples of i yellow wood (coprosma) only ono shows susceptibility. Tho various kinds of oloari.i, Borne known as iho ako-ake, behave differently, while all specimens of fuchsia, ngaio, lanccwood, lace bark, mapon, toro, pukatea, and somo other woods not so well-known locally, aro completely riddled. *In nearly all ci**es, however, it is tho outer parts which suffer most; tho sappy portions may bo almost destroyed while tlio wood nearer the heart of tho tree is comparatively immune. In order to diminish tho risk' of transmitting the pest to other parts of the building, those damaged specimens are being withd-awn from exhibition, but persons who are specially interested in our nativo woods, such as cabinet makers an 3 timber workers gonerally, may sec and examine tho sped- j mens on making personal application to the Museum authorities.