Longevity is the iron lung of a woodland tree – life support for an ageing population.
The woodlands of Dunkeld are among the most beautiful in the world. Stately old trees, scattered across grassy paddocks, frame the rugged Grampians Ranges in the distance. In another continent they could be oaks or olives, but in Dunkeld the trees are River Red Gums. Eucalyptus camaldulensis. Century old giants.
The woodlands don’t go on forever, but peter out in the grasslands to the south and west. Sandy out-wash soils from the ranges allow trees to prosper. On the heavy clays further afield, grasses prevail. The boundary between the woodlands and the grasslands – the edge of the treed lands – is strikingly clear on air photos. Google Earth shows a ring of woodlands to the west, south and east of the Grampians, with farmed grasslands beyond.
The rigid boundary
But how stable is this boundary? Is it moving over time? In many regions, paddock trees are gradually dying out, creating a “tree regeneration crisis”. If this was the case at Dunkeld then the boundary would creep slowly in towards the ranges.
To check the boundaries, I studied the 1940s air photos, the earliest record I have of the region. I re-sized a 1948 air photo so it overlaid the latest image from Google Earth, traced the boundary on the 1948 photo and superimposed it on the Google Earth image.
To be honest, I was surprised at the result. Over the past 65 years, the Dunkeld woodlands haven’t shrunk. They haven’t expanded either. In fact, the boundary between the grasslands and the woodlands hasn’t moved an inch.
Not only has the boundary stayed stable, but each and every tree looks the same in both photos. This stability is more obvious if we zoom in for a closer view. The photo below shows a paddock south of Dunkeld in 1948. I selected this area because the old photo was clear and easy to examine, and most paddocks in the region show similar patterns and changes.
The roadside on the right seems to have been heavily grazed in the 1940s, as there’s more bare ground on the road verge than in the paddocks. Back then, there wasn’t any strip of roadside trees. There may not have been much “roadside vegetation” to speak of.
Sixty-five years later, the landscape has changed a bit. There’s a new home, shielded by planted windbreaks and gardens, plus a new road in the south. But the biggest change isn’t in the paddocks, it’s along the roadsides. Strips of dense trees now line the roads to the east and south. The grasses are darker along the roadsides than in the paddocks, indicating that the roadsides (and a fenced lane-way in the north) are now grazed less heavily than the paddocks.
From paddocks to roadsides
Inside the paddock, not much has changed beyond the homestead area. With some digital trickery, we can compare the trees across the two images. On the photo below, I’ve overlaid all of the trees that were present in 1948 (in red) with all of the trees that are still standing in 2013 (in blue). I’ve offset the two colors so they can be compared. The backdrop is the 2013 Google Earth image. The comparison is striking. The paddock trees have hardly changed over the past 65 years. But trees have regenerated densely along the roadsides.
The comparison is even more striking when the colors are changed. In the photo below, the blue dots show the old trees that were present in 1948 and 2013. Green shows the new trees that have regenerated since 1948, and the red dots show those that died since 1948. Generally, the paddock trees have been very stable; most of the old trees still survive.
But not all of them. About 7% (approximately 31 of 428 trees) have died since 1948. On average, that’s a death every two years in this small area. As time marches on, that death rate can only increase. The biggest worry is: there isn’t a single new tree in the big paddock. All of the paddock trees are old. The only new trees are along the roads.
On one hand, the apparent stability of the paddock trees is a wonderful thing. With careful stewardship, the region’s farmers have saved the beautiful old trees, and preserved the region’s picturesque landscape. But this stability masks a deeper problem. For about 60 years before 1948, few trees regenerated in the region (or anywhere else), as hordes of rabbits ate the young plants. For over a century now, the paddocks of Dunkeld have been starved of young trees.
Imagine a landscape where hardly a single tree regenerated in a paddock in your lifetime, in your parents’ lifetime, and perhaps in your grandparents’ lifetime. That’s Dunkeld.
Now imagine a landscape where hardly a single tree regenerated in a paddock in your lifetime, in your children’s lifetime, and in your grand-children’s lifetime. Is that paddock also in Dunkeld?
The old trees of Dunkeld are like candles in a monastery, religiously kept alight. But with no new candles being lit, one by one, each flame splutters and dies. And when they go, we have a century of failed regeneration to make up for.
Fortunately, for my generation, old red gums are long-lived. This longevity is the iron lung of the woodlands; the life support system that keeps an increasingly old population alive. When that iron lung finally gives out, there are no new seedlings, no young saplings, no small trees – except along the roads. With no new recruits, the landscape of Dunkeld is changing from a pastoral woodland to treeless paddocks dissected by narrow roadside strips.
The woodlands of Dunkeld bear the weight of a generation gap 100 years wide. We can’t fill that gap. But we can belatedly heal it. If we don’t, the woodlands won’t go on forever, but will peter out as the grasslands move in from the south, the west, the east, and the center.
We owe a huge debt to the farmers of Dunkeld. Their stewardship has kept the trees of Dunkeld alive for over a century. But stewardship of the past creates no future for the trees of Dunkeld.
The Dunkeld woodlands need stewardship and more. They need some Succession Planning (and planting). Without a rapid transfusion of new plants, the beautiful woodlands of Dunkeld are doomed. That’s a heavy legacy for the good farmers of Dunkeld.
This story was initially posted in early 2013. My apologies if you’ve read it before. I hope you enjoyed it.
The beautiful photos of old trees in this post were taken by photographer Richard Crawley and were downloaded from the National Library of Australia’s Trove website.
You can view more of Richard’s superb photos of trees in the National Library of Australia at this link and at Richard’s personal website. I am most grateful to Richard for his permission to use his photos in my blog. The copyright (all rights reserved) for the red gum photos is held by Richard Crawley.