VOLCANIC WASTES

Evening Post, Volume CXIII, Issue 18, 22 January 1927, Page 13

VOLCANIC WASTES

OSHT .MANTLE GROWS

BOTANICAL RECONQUEST OF TARAWERA "

CO-OPERATIVE METHODS O¥

NATIVE FLORA

(By E. Phillips Turner, F.E.G.S.) In the forty years that have elapsed sineo the Tarawera eruption, tho great grey wastes of ashcovered country have yielded increasingly to the attack of pio- ■ neer vegetation that paves the way for higher growths—so that to-day the lower slopes of the mountain can show patches of bush 1 up to 30 feet in height, including pohutukawa, "honeysuckle" (rewarewa), and even an Australian •eucalypt. The disseminating agencies ato firstly wind, Secondly ■ birds. Beconquest by vegetation, of the volcanic"waste :is of great bo- ' tanical interest. s • -1 was an assistant on 'the survey of the railway from the Waikato to Eo- ' torua in June, 1886; Our camp was at Ngatira, on tho Waikato side of the Mamaku forest. Being awakened on the night of the eruption (10th June) by the "terrific reports and the earthquake, we turned out of our bunks to find tho whole sky in the east illumined by brilliant electrical discharges. Being 35 miles in a straight line from 'Tarawera, and there being a high intervening plateau, we ctfuld not see the actual dischaTge of the incandescent material. In the afternoon of. the following day, after we had learnt that a volcanic eruption on a large scale had occurred at . Tarawera Mountain aid.-at Botomahana, a party of four of'us loft camp and tramped thirty miles by a Maori track through the Mamaku forest to Eotorua,. arriving there at about 9' o'clock at night. Nest morning the writer, with a companion, started from Botorua, ■ where there was merely a thin deposit -of volcanic ash. However, this rapidly ' increased in thickness, and at the c Blue 'Lake -"(Tikitapu) was several feet in depth. The volcanic deposit in this locality was of the .consistency of wet cement, and as at each step one sunk • to the knees in it, the difficulty of progress can be imagined. Not a vestige of animal or vegetable life was to be seen, and the waters of Tikitapu ■were of a dirty grey colour with fragments of pumice floating on them. To add to the awsome scene, every fewminutes there were large avalanches of volcanic mud, which fell from tho sides of the steep surrounding hills. RUINS OF WAIROA.

■ However, after the stiffest walk of my whole surveying experience, we reached the site of the "Wairoa village on the shores of Lake Tarawera. Here the mud .was from five to fifteen feet in depth, and only shattered remains of the cottages and whares of this formerly picturesque village were to be seen. In every direction there was one vast desert of the mud. Time could not be obtained to join any of the exploring parties! so the return tramp to 'our camp at Ngatira'had to be made. In the year 1900 (fourteen years after the eruption), being on the' Lands .and Surveys-Department staff, I was sent to Eotorua to undertake surveys • pt the whole country between Lake Ta- "• irawera and the Waikato Eiver at Orakeikorako. One of my camps was in the ruins of the old hotel at Wairoa, and while surveying from there we discovered a large- Maori canoe covered up by mud at Kaiteriria, on the southern end of the Green Lake (Eotokakahi); we cut off the rotten part of the canoe, patched up the sound part with boards, padTdled it. across Eotokakahi, and then dragged it along the creek from Eotokakahi down to Tarawera Lake for use in traversing the shore boundary.

Haying an urge to examine the condition of Tarawera Mountain, we cross-: ed Tarawera Lake in this coracle and ascended - Tarawera via: the high rift. caused by the eruptions «i)f 1886 in the southern part of the mountain, which reaches at its summit a height of 3700 feet:rv';.-\ ■';.;.. ■■: ■■ ::-:."-<.v;-.'-.-:-' r.- ..--

t WAEM AFTEE P.OTJBTEEN 1 YEAES.

The climb, to a yioung man whose , duties, caused him to be 'continuously''tramping over lough - virgin (country, ] .was a : trifle,- there being "only about '■ •_,•/600 .feet of. steep loose scoria, threequarters of the. distance to the top. At ■■ .this' place, and abput eight inches below the surface, the ground was still warm,:; showing that fourteen.;. years .was not sufficient to make coid the subjacent rock which may have had a tern--' i perature of; about 3000 deg.= at; . the. time of the eruption.'•■ Steam Was being emitted | from : the bottom*; of the rift.:l do not remember that in 1900 there was any live vegetation on that . part of the mountain up which I went, ! but the hills' near the Blije and Green . Lakes, and to the north-west of. Tara- .. ,wera, hadUa,fairly abundant growth of tutu, makoniako, and fern. The clumps of forest near the Blue and Green! . Lakes had shed the mud with which '. it was coated at the eruption, and had put forth new shoots with copious fol- . iage; all rata's—which, might have been expected to be the most tenacious, of life—were, however,. killed. On the south-western shores of Tarawera. there wasa sparse growth of tutu and toitoi. ;.'_-,; The whole: country had been..'dissected by "washouts," ranging from -one foot to 30, feet in depth, the' intervening spaces were often razor-backed, and the country was extraordinarily dim-" ' cult to travel over. To, get to.the far side o£ some of the largest"washouts" one had "to -go round a mile, as. the walls were perpendicular. At this, time 'the water- in Botomahana Lake, was not high enough to make the.."Banded '"Hill'?, an island, there being a narrow neck between it and ' the mainland. . Waimangu Geyser had not then devel- - oped, but less than a year : afterwards, .;;.when taking trig observations' from - the top of a mountain called ITaparangi, I saw over the Tumuniii. Bange several successive immense discharges of steam shot overlooo feet into the sky. I was. shortly afterwards knocked over by a severe, attack of typhoid fever, or I would have made a trip to the locality to find out what had really happened... Some months afterwards, while recuperating in' Australia; I read of the „ discovery by Dr.. H. Haines of a gigan- , y tic geyser near Eotomahana.' . -. TEEEACES BLOWN TO SKY.

While in the locality I made a rough survey of Kotomahana Lake. As it had afterwards bpen suggested that the "White and Pink Terraces had not been destroyed, I made a tracing of. my plan, and, by imposing it on a plan made of the lake and terraces as they existed before theeruption, it. was conclusively, shown that the boundaries'of the original lake were well insido- the periphery of the new lake^—it! had functioned as an explosion crater in 1886— proving that the terraces ■ had been blown into the sky and distributed in fragments over the surrounding country.- The new Botomahana Lake is about four miles long, with a maximum width of about two miles..

. .On .Hew - Tear's . Day of. this year,': via -company with my son (Dr.. K.G. Phillips Turner), I took

the opportunity of' a short holiday at Eotorua to ascend Tarawera again, and I was much struck with the progress that re-vegetation had made in forty years on a-soil that was previously without visible plant life. Landing on.the shore -at' the south-western part of the mountain, I found the cliffs bearing numerous pohutukawa tree? In several places "there were considerable areas of young forest about thirty feet high. The 'chief trees were pohutukawa, makomako, tutu, mahoe, reware^ wa, manuka, tawa, tree ferns, tawhero, etc., with an abundant undergrowth of shrubs and ferns. In other places tutu and.manuka, with ..smaller shrubs, occurred in thick' shrubberies or scattered about singly; the beautiful Gaultheria (oppositifolia), with flowers like lilies of the valley, was abundant and occurred intermittently even to v.the summit of the mountain. At one spot near the base was,an Australian gum tree- about forty feet. high. Numerous herbaceous plants were seen,' lessening in frequency as the' top was approached. '.: ' ' , „ . -

The best precursors of plant colonisation on such stony and ; saiidy tracts ;are, however, various small species of plant related to the daisies and called Baoulia. They grow iii the driest loose sands and among rocks, extending as a thick mat and thus binding the mobile sandy soil and forming humus. The mat forms a safe "nidus" for wind-blown seeds, e.g., catsoar,.manuka, etc., which germinate and which form protection for other plants; thus the land gets gradually restocked with a more or less abundant plant growth.

HOT SPOT NOW COLD. The ascent on this occasion, as in 1900, was made via-the huge fissure on the southern end of Tarawera Mountain. At-the locality where the hot ground was in 1900 the subsoil was found to be quite cold. There s was not time on the present visit to descend to tne bottom of tho crater to test if there was lingering activity, but shrubs of tutu : were seen on the -walls of the fissure and in tho crater on the summit of the mountain.

Wild horses, rabbits, deer, and wild pigs are on the.(.mountains, and these animals doubtless much' retard the revegetation of the locality-. As has been shown by Mr. B. C. Aston, who ascended the mountain 'in 1913 and 1915, tho chiefs agency in the colonisation of the plantless areas of this region is wind, birds coming nest in importance. Many of the pohutukawa trees are probably re-growths from stumps of trees which ■were covered up by tho eruption, but which have since become exposed by erosion.

Starting early from Eotorua, the trip can be made easily in one day. Those not interested in botany will find there is a great fascination in the awsome craters, and on a fine day there is a most magnificent view of the surrounding country, as far asEiiapehu in the south, Te Aroha Mountain in the west, and White ■ Island in the ' north. The climb is easy, but the scoria requires that strong boots be worn.