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.
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.
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 during the period.
The comparison is even more striking when the colors are changed. In the photo below, the blue dots shows 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 the 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.
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 for all of the red gum photos is held by Richard Crawley.
Ian, I’ve been following your posts for a few months now. Always an interesting read. This one about the Dunkeld woodlands is similar to the situation occuring in the Hunter Valley of NSW, and doubtless across many other parts of Australia, but for one difference. In some areas, retained trees in paddocks that have had grazing eased or removed are now producing new forests and woodlands, but the canopy composition of these is entirely dependent on the identity of those retained trees. If it is an ironbark, an ironbark forest regenerates; if a box, a box forest (and I deliberately say ‘forest’, as the density of young growth is a long way off sorting itself out into a ‘woodland’ structure). What may have been originally a box-ironbark-redgum landscape is being reshaped into distinct monospecific forests defined by those originally retained trees. An interesting phenomenon.
Hi Stephen, thanks for your comment and great observation. I haven’t been to the Hunter Valley for a long time now, so it’s great to hear from regions I don’t know well. I suspect that the phenomenon you are observing may be occurring in many regions. It seems similar to the changes in grey box woodlands in central Vic, as I described in a blog last year: https://ianluntresearch.wordpress.com/2012/10/21/the-dirt-ring-photo-blog/ In some place, some species regenerate far more abundantly than others. We seem to get lots more grey box regeneration than ironbark regeneration in much of central Victoria I think, which means that tree diversity is changing too. It will be great to hear what other readers have to share on this topic too. Thanks again and best wishes, Ian
Great and sobering post, Ian. With many of the paddock trees seemingly well in excess of 100+ yo and some possibly many times that age, I wonder what you think the window of opportunity is for regen/replacement to occur, without losing too much more structural diversity. Many of the big, old trees certainly still look healthy (from this distance) – have they got another 100 years in them?
Hello Bert, that’s a great question. Unfortunately, we don’t have any accurate information on how old most paddocks trees are, as eucalypts are very hard to age accurately, especially big old trees. Similarly, we don’t know how long trees will last before they die. The most prudent approach would be to get new plants in the ground as soon as we can, as the sooner plants are established, the bigger they will be when old trees die. Best wishes Ian
Hi Ian, the lack of tree recruits in paddocks/fields is something that’s been bothering me for a while, and it’s absolutely fabulous to see some evidence for it. I’ll be spreading this post around a bit, those images speak a thousand words.
Hi Melinda, thanks very much for your comment. It’d be fantastic if the blog encouraged even one landholder to promote more regeneration, so the woodlands can survive into the future. I am very grateful to Richard Crawley for letting me use his photos, as his images are really beautiful and powerful. It’d be amazing to see a huge print of many of his photos. Best wishes Ian
Hi Ian, thanks for posting (yet again) a thought provoking piece on observations of change (or the apparent stability) in the vegetation community around Dunkeld. As always since we are really only getting a short term view of the responses in these various communities it is hard to be definitive in even preliminary conclusions drawn on the observations…nevertheless your thoughts and informed perspective is extremely valuable and hopefully will add to the conversation around what has happened to the Australian countryside, what will happen and what this means for the broader ecology (us included).
Hello Sean, thank you for sending in a comment. While there is much that we still don’t know (see, for example the comment from bertbohosouth, above), the 60 year comparison from the old air photos does give us a valuable perspective on the landscape. We can be sure that trees are getting older, are steadily (although slowly) dying out, that they are not getting replaced, and that sooner or later the rate of death must get faster. The longer we watch and wait, the more we stand to lose. I do hope that the article adds to the conversation around what has happened to the Australian countryside, as you indicate, but it would be even more encouraging if we could add to the activity and promote further change don’t you think? Thanks again, best wishes, Ian
An extremely interesting and salutary story. The addition of scale bars to the various aerial images would be helpful.
Hello Deb, thanks for commenting! Wooops, my mistake re absence of a scale. It reflects my limited ability to manipulate images in GIMP – re-coloring was quite a challenge for me. When I get back to my computer and google earth, I’ll measure the widths of each of the photos and will add a note in the captions so they are easier to interpret. Best wishes Ian
You have made some good points about the stability of the old woodland trees and about the farmers doing a good job of keeping them alive. I’m only confused by the idea that you think there is some urgency to change anything.
As you said only 7% have died since 1948. At that rate, even with no replacement it could take another 200 years for all the old trees to die. I don’t see how you can presume that the rate of death will increase unless you have some extra knowledge of the remaining trees relative ages and health. The rate of death, could decrease.
It seems that there are also presumptions being made that natural regeneration should have occurred because it has occurred on the roadsides, and that grazing is the only influence that prevented this from occurring in the paddocks.. Roadsides have added soil/vegetation disturbance, through traffic, water-shed from the road itself, and usually have very unstable vegetation which allows excessive and frequent regeneration where it otherwise would not occurr. They are not good examples of “natural”.
Isn’t it also possible that once every 100 years, 200 young trees come up and survive? Maybe there really is absolutely nothing to be concerned about. The frequency of natural regeneration events within these woodlands might be naturally very, very low. It certainly is in the drier areas.
So it seem so me if the land manager/s of this land were to plant (or protect) initially 31 seedling trees (to make up for lost time) and then two young trees each year thereafter, they would be taking a scientific approach to avoiding the doom that you have envisaged here. The rate of tree planting/protecting might need to increase if after another 60 years some increased rate of death is observed, or decreased/ceased if some natural regeneration event occurs. Such an approach would be both economically and socially very acceptable.
How many Old-growth woodland remnants in public ownership, where the aims are solely conservation, can boast a rate of old tree death as low as these grazed farms? If we value old woodland trees we should look at what keeps them alive as the absolute priority, and this seems like a good example of old tree care.
Hi Eris, thanks for a great comment. I fully agree with your last sentence – the farmers of Dunkeld have done a wonderful job of keeping old trees alive for a century, which is certainly an outcome that we haven’t achieved in lots of other regions.
However, keeping old things alive is only half of the job. Unless we provide opportunities for ongoing regeneration, we can’t replace those trees that do die. Unfortunately, a basic fact of life and death is that death rates inevitably get higher as organisms get older, so sooner or later, the rate of loss must increase.
Climatically, there have been many opportunities for regeneration in this region over the last century, so the absence of regeneration is most likely due to grazing, as has been shown in many other regions.
I don’t know that it’s very useful to contemplate what is ‘natural’ or not. The key question is – what type of landscape do we want to see in the future? If we want a landscape with many big old trees, then we need to encourage replacement trees now, so that the new trees will be big, old and full of hollows, by the time that the existing old trees die. If we wait until lots more trees do die, then we will replace paddocks full of old trees with lots of young ones.
If we do want to keep this type of landscape, we can encourage regeneration now, to maintain the landscape pattern, or we can wait until things get worse, and try to belatedly make up for lost time. Waiting and watching doesn’t seem like a viable option to me. Best wishes Ian
I was supporting the idea of encouraging replacement trees. I was just questioning the urgency and highlighting that due to the fact the tree are very long lived, and death rate very low, the rate of replacement needed is very easilly achieved with minimal effort or changes to management.
Changes to the management, even when done with the best of intentions would very likely hasten the death of the old trees, as it has done so well, in so many other places where regeneration has been encouraged.
Hi again Eris, I think we’re saying the same thing in different ways. The take home message of the article is the need to encourage succession planting, and there is no mention of any broader change to land management.
Why the urgency? To paraphrase the old farmer’s saying, “You can’t start succession planning at a funeral. It’s gotta start at birth”. In this context, planning = planting, and we’ve got a generation gap up to a century wide to make up for. We need to get moving. Best wishes Ian
Hi Ian at a Conservation we manage at Mt Ridley near Craigieburn we have a 10Ha Red Gum Grassy woodland site on the headwaters of the Malcolm Creek a tributary of the Merri Creek. It was formally grazed for well over 100+ years and within 10 years of destocking thousands of Red gum seedlings have return in thickets around the older trees. Unfortunately there is not a heap of diversity on the site. We are slowly revegetating and doing burns to manage the grassland values. I will try to dig a few photos up to send to you. It would be interesting to de stock the property near Dunkeld to see what would happen.
Thanks for your comment Jason, it’d be great to see your photos. Managing tree densities is certainly a challenging business. On one hand we have lots of areas where we desperately need to increase regeneration. On the other hand we have some areas where trees have regenerated extremely densely, which is often not desired. I think we’ve still got a lot to learn about how to manage between these extremes. the work you are doing is part of this learning process. In the future people will learn from your experiences at Mt Ridley and elsewhere, so keep up your great work. Thanks again and best wishes Ian
Ian thanks for drawing my attention to this, I wish it had been written when I had that discussion with Malcolm Fraser in around 1979/80; I could have just given him the reference. It gives data to what I was suggesting and documents the phenomenon we see around very wide areas of the pastoral landscape. In talking about it I often talk of ‘dying landscapes’ and the problem for most people is to understand that unless recruitment is actively managed, as you suggest in responses above, we will end up with no paddock trees and simply a halo around the roadside verges, and in now-disused TSRs.
Thanks again for writing in Max. If Max’s comment about our ex-PM sounds a trifle cryptic, readers may wish to read an earlier comment that Max made on another post at this link… https://ianluntecology.com/2013/06/13/natural-regeneration-connecting-regional-australia/ Best wishes Ian