Obituaries Australia

[John Maxwell] Max Gilbert joined the Tasmanian Forestry Department in 1934 at the age of 21. He arrived after graduation and as the largest bushfires in Tasmania’s history were burning over huge areas of the State; no doubt this event profoundly influenced his thinking on the importance of fire in forest management. His early work was in applying the scientific knowledge he had gained and in organising fire protection. Later, in the late 1940s and 1950s, he made significant contributions to improving the quality of radiata pine plantations in Tasmania through better nursery practices, selection of plus trees in plantations, establishment of progeny trials and the development of seed orchards. He became Fire Protection Officer in 1945 and the Head of the Silvicultural and Fire Protection Branch in the early 1950s. Max was in charge of the Forestry Commission’s silvicultural research activities until his retirement in 1974.

Max’s best known contribution to Australian forestry lies in his work on the practical methods to achieve eucalypt regeneration after logging in wet eucalypt forests, based on a sound understanding of the natural processes. In the 1950s, the regeneration of cutover eucalypt forest was often unsatisfactory and the ecological and silvicultural requirements for achieving good regeneration were poorly understood. In 1954, Max received the first Australian Newsprint Mills Fellowship to study regeneration of wet eucalypt forests in the company’s forest concession areas, particularly the Florentine, Styx and Tyenna Valleys Max’s post-graduate studies from 1955–58 resulted in the first Ph.D. on forest ecology to be awarded in Tasmania. This work was a landmark event in the history of ecological research generally, and particularly in forest ecological research in Tasmania. Max made a detailed analysis of the geology, climate, forest types and role of fire in the mixed eucalypt-temperate rainforests of the Florentine valley. He concluded that the ecological processes operating there were best explained by the traditional “succession and climax” theory first mooted by Clements (1916) and later modified by others to the “fire climax” theory where fire was a re-occurring event. In the mixed forests of the Florentine valley, the hypothesis was that fire is the major factor preventing the general attainment of climax vegetation—temperate rainforest. His story of succession in these wet, mixed forests on soils of moderate to high fertility is summarised from his Royal Society of Tasmania paper (Gilbert 1959), a seminal work and one of the most referenced papers in Australian forestry science:

• If an area of mixed forest (eucalypt forest with a rainforest understorey) remains unburnt for 350–400 years (the life span of the main eucalypt species) then the climax condition is achieved;

• If an area is burnt infrequently but with an interval of less than 350 years it remains under mixed forest. The forest is destroyed by each fire but the species present in the fully developed mixed forest regenerate immediately after the fire;

• With a fire frequency of once or twice per century, the mixed forest is replaced by eucalypt forest with a broad-leaf understorey characterised by Pomaderris, Olearia and Acacia instead of climax rainforest species;

• Still more frequent fires, perhaps at 10–20 year intervals, will not only prevent eucalypt forest progressing to mixed forest but will maintain E. obliqua and E. delegatensis at the expense of the much more fire sensitive E. regnans.

The findings of Max Gilbert and Murray Cunningham and subsequent operational trials resulted in the clearfell, burn and sow system for wet eucalypt forest. This system has successfully established well over 200 000 ha of regrowth forests in Tasmania. Max, Murray and other colleagues developed the first systematic harvesting and regeneration systems for Tasmanian forests that have since been broadened to include a range of partial harvesting systems.

In an interview in 2005, Max explained: “What I was really interested in was that the management and treatment of the forests could be improved or be made much better because we had a better knowledge of why the forests are as they are today”.

He recalled that when he began work in the 1930s: “People had very little idea about what was going on in the bush and as to whether anything should be done to get regeneration, I don’t think entered anybody’s mind. The only action I remember being taken was that heaps of heads of felled trees were burnt if there was a suitable opportunity. I’ve forgotten whether that was done as a fire protection measure or in the hope that there would be some regeneration obtained. But in 1934, any ideas as to how to regenerate cut-over forest I’d say, by and large, did not exist.” (Cubit 1996).

The importance of light and fire to wet eucalypt forests began to dawn on Max when he discovered that the biggest myrtles in a forest he was studying were the same age as the eucalypts. “I remember thinking about this and I decided that fire had something to do with this and scratched the litter of the surface soil” Max recalled. “There was no sign of charcoal on any of the vegetation, but when I scratched the surface I found scattered bits of charcoal and it became pretty obvious that the forest originated in the regrowth that comes after a really hot fire killed everything. And so if you like, the present mixed forests are the children of destructive fires of similar types of forests. This improved knowledge was a great help in deciding how to develop better management of the forest.”

The Perpetual Gilbert-Cunningham Trophy was introduced by Forestry Tasmania in 2005 to be awarded annually for excellence in growing native forests. The naming of this award recognises the key contributions that Max Gilbert and Murray Cunningham made in developing a solid silvicultural foundation for sustainable forest management in Tasmania.

Max Gilbert treated everyone in a friendly way and became a role model for many young foresters. His fine sense of humour is fondly remembered by those who worked with him. Max had a great love of the bush and was a keen observer with a questioning mind, qualities which underwrote his great success in forest research. Australian forestry has been indeed fortunate to have his contribution to forest management over many years. Perhaps an even more important contribution was his influence on the generations of foresters who followed him.