Leader: Dr Ruth Lawrence. 22 Jan, 2006.

The trip commences. It was an excellent day under the tutelage of Dr Ruth Lawrence. The day commenced with a 7.30 am departure from Feathertop Lodge, travelling down the Ovens River Valley which is only 300m above sea level. The bus had to contend with cyclists (over 1000 in an annual cycling event), mainly travelling towards Falls Creek but some returning. David did an excellent driving job under the circumstances, with the cyclists on a winding hilly road.

Tawonga Gap and Mt Bogong. The bus stopped at Tawonga Gap where we had a panoramic view across the Kiewa Valley and the twin towns of Tawonga South and Mt Beauty, to Mt Bogong which is the highest peak in Victoria. At Tawonga Gap Ruth showed geology maps of the area and gave us an overview on the valleys and the formation of the land masses. Unlike the Ovens River which ends in a pinched valley, the Kiewa River broadens out at its head into a wide plain. A thrust fault defines the boundary between the forest and cleared land. The area south of the fault has been uplifted, not as a single event but a series of uplifts over a vast period of time. Mt Bogong south of the fault is the highest point because of the uplifting that has produced a ramp effect of peaks. Rivers have eroded the landscape since uplift. The terraces that define Kiewa valley are evidence that uplifts occurred spasmodically over a period of time.

Australian High Country is a plateau-like in that it has high plains rather than sharp peaks as in Europe, South America and New Zealand. This is due to the various uplifts that retained plain-like character after each lift event.

Fire at the lower elevations. The mixed species forest above the town of Mt Beauty have recovered quite well from the January 2003 fire. Epicormic growth has advanced to the stage that there is only minor evidence of the severity of the fire. Stark stags of the Alpine Ash in the montane elevations bears witness to the intensity of the fire. Except for a few pockets that did not burn, the forest is a ghostly stag with a dense undergrowth of regeneration from seed (the only form of regeneration for Alpine Ash). This regrowth up to a metre and a half in height has a conspicuous bluish tinge in the juvenile foliage with the upper copper-coloured making for a splendid colour effect.

It is interesting to note that Alpine Ash requires a maturity of 20-25 years before fruiting, so any further fires in the next two decades will have a devastating effect on Alpine Ash forests.

After the 1939 fires the Alpine Ash was harvested for timber. This has not been the case after the 2003 fires. The National Parks management has decreed that fire is a natural event and therefore nature must be left to run its course. It will take many years for the tree stags to decay and fall. They will be a hazard to bush walkers for quite some time. It is probable that termite populations have been depleted by the 2003 fires. If this is the case then fallen trees will take longer to decay on the forest floor. This will add to the accumulation of combustible material, to create more intense fires in the future.p>

Tree ferns were the first plants to produce green. Sprouting began two weeks after the fire. Tree Fern growth is from the centre of the plant. Dead outer material shields living material from the heat of the fire.

Snow Gums. As elevation rises on the road up to the Falls Creek the Alpine Ash forest gives way to the Snow Gum forest. Snow Gum is the predominant tree species in the sub-alpine region. Snow Gum has lignotubers, and is able to regenerate quite well. New growth was up to a metre in height.

Water Run-off and fire. According to Ruth, the effect of fire on Alpine Ash forests as far as water run-off is concerned, can be up to 30 years. Regrowth is a heavy consumer of water and therefore run off into the dams is reduced during major regeneration period. Therefore fires have two significant detriments.

• The greater erosion immediately after fire event which results in siltation in the dams.
• Reduced water flow into the dams.

The power stations were idle on the outward journey but were in operation on the homeward trip. Turbulent white water was cascading down Rocky Valley. These power stations are peak load only and had come into operation due to the heavy demand in Melbourne caused by domestic air conditioner use as a result of a forty degree heat wave.

Frost Hollows. Rising above Falls Creek village a domed basalt outcrop could be seen on the left. The basalt is the same as that at the Ruined Castle. Ruth informed us that we were now in an inverted landscape. The remnant basalt gave no indication of the actual site of the extinct volcanos that had erupted long before the various uplifts that had created Mt Bogong. The Bogong High Plains contain sub-alpine vegetation with Snow Gums on domed hilltops and grasslands in the shallow valleys. The valleys being treeless are a unique Australian feature; an inverted treeline that is found nowhere else in the world.

Originally it was believed that trees did not occur in the shallow valleys due to burning by aboriginal people. Recent experiments, however, have disproved the earlier concept. It is now known that the valleys are free of trees because of the flow of cold air drainage on late afternoons and evenings down the valleys. As a result, the soil temperatures for a greater portion of the year are too cold for tree growth. This was shown in tree-planting trials using Snow Gums in the valleys.

Ruth informed us that there is very little true alpine areas in Australia where there are no trees. (Alpine = above the tree line). The top of Mt Bogong is an example of a true alpine region.

Cattle. Ruth explained the operation of Cattle exclusion plots that were established in 1940 to 1970, to test the impact of summer grazing of cattle on the Bogong High Plains.

Recent trials indicated 300 head of cattle across the Bogong High Plains was compatible with grasslands regrowth. In 1940, 10,000 head of cattle grazed the Bogong High Plains. When the practice was discontinued the number was 2,000.

The decision to discontinue cattle grazing was made at a political level on the basis of protecting the water catchments. Most of the group followed Ruth on a five kilometre hike to see a stream flow guaging station halfway on our semi-circular walk. This station had been closed in the 1960s but had opened again recently.

Cattle have had an impact as evidenced by the thickness of the peat bogs and projecting rocks that would have been mostly covered before the advent of grazing. On the higher ground the soil is very friable and would have been affected by both wind and water erosion as the result of cattle hooves.

Ruth recounted a story of a horseback tour in 1868 when a rider recorded that his horse sank up to its neck in the peat in the low parts of the valley. This would not occur today. It is conceivable that the height of the landscape could be up to a metre above current levels. It is most likely that before cattle grazing there was no channelisation, water being released much slower by percolation, rather than seepage into channels as occurs now. It is probable that channelisation commenced around 100 years ago.

Looking across the Bogong High Plains one observed the amazing contrast between the stark Snow Gum stags on the burnt areas and the green of the preserved areas that had somehow escaped the ravages of the 2003 fire. Patches of deep green on the slopes immediately above the valley bogs showed sphagnum moss is regenerating well.

Wallaces Hut. After lunch, in the presence of vast numbers of bush flies, under the shade of Snow Gums, 20 of the group took the long trail to Wallace Hut. It was originally constructed of Snow Gum vertical walls and shingle roof. It must have been an amazing feat to find straight poles if the current bent nature of Snow Gum stems is an indication of the character of these trees at that time.

We were told that the Wallace family had cattle occupying the area during the summer seasons until the 1920s. The Wallace family took up the grazing lease after the Lands Department in 1888 invited applications for lease of grazing lands in the High Country. The Wallace family is still farming in the Kiewa Valley. After the lease was abandoned by the Wallace family the hut fell into disrepair but was restored in 1930 by Joe Olsen who put on the corrugated iron roof and built the lean-to wood shed. Joe Olsen occupied the hut continuously for 12 years in his job associated with the establishment of the hydro-electric scheme. The Outward Bound movement took over the hut in 1950. The bitumen paper lining would have been placed inside at that time. This material came into common usage for sheds during building material shortages immediately after WWII, when it was used for cladding and roofing for small sheds and poultry houses.

Back to base. Finally we reboarded the bus at 3.30 pm at the conclusion of another wonderful day.

Edwin Dell

1: Tree Fern. Bon Accord Track.
2: Wallace's Hut among Snow Gums. Jan 1987.