Old street trees with the patchwork method

We can attest that we cherish the importance of trees and street trees in particular, and we recognize the sentimental value of decades-old, pioneering trees. Trees with a presence, with a whiff of history, that have already taken root deeply, both literally and metaphorically. Beyond the emotional aspect – some qualities are only expressed in many trees’ adulthood, after years of growth and establishment. Be this the adult display, the canopy that reaches impressive dimensions, spectacular flowers etc. Furthermore, difficulties in adapting and other phenomena that characterize young trees and pass with the years, are already gone.

In spite of all these reasons, and maybe even because of them, our opinion is that a street tree should not be left at any cost. Sometimes, it’s the right conclusion that it isn’t possible to realize the benefits of the tree and enjoy its full potential. The time has come to give up, not to insist, and to replace it.

Patchwork

Fig trees, Dalbergia sissoo, Albizia lebbeck, Fraxinus uhdei, Jacaranda and Brachychiton are all old street trees that are common on the streets of cities in Israel. These are ostensibly classic, pioneering street trees that were planted with the intention that they quickly beautify and save the city streets. But sometimes intentions have little to do with reality. You can frequently find entire boulevards of trees whose dimensions do not match the appearance and vitality expected from their age. Some are crooked and distorted, others are broken, or degenerated, and many others indicate to a professional eye that their future is not promising. The lack of uniformity in their appearance is strange and jarring in view of the existing information regarding these varieties. There are fig trees, for instance, that are 60–70 years old that have the canopies of a 10-year-old tree. Other varieties that are supposed to fulfill their growing potential and reach heights of 20–25 m with a wide canopy only reach a height of 5 m with a cluster of green foliage that is too small. Because instead of the natural look, they are pruned into “pom-pom” circles, or in straight lines, sort of like squares. What’s the point in a boulevard and shade tree that has been designed over the decades as though it were a small shrub and young?

Adult trees (some even decades old) with hacked-off canopies that don’t suit their age and lacking all proportions to the trunk

Unfortunately, this tendency is widespread. Jacaranda, Peltophorum, Pterogaillonia, Dalbergia sissoo, Albizia lebbeck, Fraxinus uhdei and Brachychiton: all of these trees have three things in common. First, they have all been in Israel for a long time. They are amongst the “older immigrants” – the first after Eucalyptus and Ficus trees. This was well before we had a wide and accessible variety of other types of trees available from nurseries. And these are absolutely great, sturdy and magnificent trees with character and considerable importance. The second thing they have in common is a fast capacity for growth. Perhaps too fast … And the third thing they have in common, which is the most important, is that we had no idea how to treat the trees well so they would treat us well in return.

In retrospect there was a great lack of understanding. Thus, the lack of understanding how to plant the trees led to unsuitability with the urban landscape. Peltophorum dubium, and Brachychiton rupestris were not intended to be planted along sidewalks; they’re just too big. Not knowing how to plant – planting beds and not entire segments in a subbase that strangle the trees and prevent them from developing. Thousands of Jacaranda and Acer trees remained frozen in city sidewalks to attest to this. And as for design – there was no awareness of the subject. Dalbergia sissoo, perhaps one of the trees that is most identified with this, is a great tree, a striped street tree that today isn’t used because of previous failures. The same is true of Tipuana tipu. If only we had been aware of the proper way to care for it, we would today be able to see boulevards of impressive adult specimens of these trees on the streets of Israeli citizens, and their reputation wouldn’t be damaged.

Today we see many examples of over-pruning of all of these old trees. They grow quickly, faster than we can handle. These are Jacaranda, Pterogaillonia, Acer and Dalbergia trees. The lack of awareness of proper design and pruning from their beginning as street trees has led us to a sad default setting: we are mowing down these trues due to helplessness.

This kind of trimming is excessive. It entails massive cutting and pruning of the tree’s frame, which eliminates many branches, shortens the remaining ones in an extreme manner, and produces a canopy form that is much smaller than the natural appearance of the tree. When done, this is a death sentence for the tree. Its lifespan is drastically shortened (if it manages to recover from the excessive trimming), and the likelihood for pest infiltration and decay heightens dramatically. Actions to restore or rebuild the tree’s canopy are nearly impossible, and they do not justify the required investment of close, professional and intensive care over many years.

The main reason for this drastic over trimming of classic street trees is the constant struggle over the years with large and heavy branch fragments, unaesthetic growth of branches that grow randomly and asymmetrically.

These phenomena, in addition to a distorted and strange trunk and a lack of uniformity in the appearance of the trees on the boulevards, are evidence that we were on the wrong path. These are all the result of a lack of treatment and design over the years. Some times, there just wasn’t a choice other than to settle for an adult tree with a static, compact, artificial appearance, clearly different from its natural shape, and therefore devoid of many important properties of a street tree.

So with this state of affairs, some will say: “Ok, the time has come to improve. Let’s prune, make corrections, support and water, and in a few years, we’ll return these trees to their former glory.” In practice, this doesn’t work because it’s not practical. Indeed, it’s clear that a crooked tree will not straighten. The attempts to prevent breaks and unaesthetic growth in a tree whose base has not been properly designed have a price. The excessive trimming discussed above results in dozens of branches emerging from where cuts have been made and initiates a cycle of repeated need for intensive and complex operations of thinning and the removal of the unwanted branches.

Attempts to take over and control pests and decay that come as a result of the trimming are also routine and intensifying: to the point of losing control, when it comes to street trees and such a widespread phenomenon. In practice, in cases like this the diseases and negative effects will only worsen, the variation in appearance will continue, and branches will continue to break. And the compromise solution on the ground – continuing to excessively trim … boulevards of adult trees, rich in greenery, providing abundant shade and a tunnel-like appearance, remain unrealized possibilities, just wishful thinking.

The critical years for proper design are when the tree is very young. This is the window of opportunity to prevent overly rapid, uncontrolled growth, to balance the frame, to trim it so as to create optimal branch angles for strength and to design the tree so that it grows throughout its entire life such that the foundation of its frame is already optimal and all that remains is to reinforce the situation.

On the other hand, a tree that grows without control, too quickly and without designing intervention (especially in the narrow and restrictive spaces of sidewalks and streets) may be weaker. Without professional intervention, the branches grow without order or method. This tends to be reflected in an unbalanced frame and problems with balancing weight and/or too many branches close together on the tree’s main frame and/or overly acute angles of branches. All these create weakness and a high likelihood of breaks.

This is all the truer when many trees arrive in the field already damaged (see the article “Trees in city streets – awareness and proper care).

It is clear that old trees have already passed the point of no return. The situation cannot be corrected. The base is not balanced and not built correctly, and it is no longer possible to achieve the theoretical potential that the tree should have. So the policy of excessively trimming it continues. The branches break or are likely to. So as a metaphor – a patch is put on it. And the next year, this repeats, and we’re already looking at a patchwork tree. And so on.

Improper pruning, incorrect design and an imbalanced frame

The painful solution

The resulting situation is absurd. Over many years, capital has been invested in maintaining trees. At a rough estimate, tens of thousands of shekels have already been invested in many boulevards in the treatment of each tree (individual trees!) and all this to achieve a result of trees that do not show any properties of street trees. So with all due respect to nostalgia, we wonder, why are we continuing to maintain those trees? Why don’t we replace them with new ones?

The feeling is that we’ve fallen into a routine devoid of any logic of repeated treating, again and again, which is incompatible with the present needs. Like continued treatment with painkillers rather than treating the root cause once and for all. Or in our case – uprooting. And planting a new tree. A proper one that is well-designed with all the desired properties.

Incidentally, every calculation shows that the uprooting of the adult tree, the removal of the tree and the stump, the redevelopment of the street infrastructure and finally the planting of a fresh, quality young tree will be significantly cheaper and save money, from every perspective through which we choose to examine the issue. The expediency is clear and better than any repeated pruning of the boulevards of damaged trees we are talking about.

If any of our friends with green ideologies, nature- and tree-lovers, are angry at our approach, which calls for uprooting a great many trees, it is important that they understand: we have been living in the world of transplantation and agriculture for three generations. We’re not approaching this lightly. We’re living it! And from this perspective, we assert that the time has come to change. There is no harm to the green lungs of the cities. To the contrary, this is a call to repair, improve and strengthen them.

Case study – Dalbergia sissoo

We’ll take Dalbergia sissoo as a sort of case study. A tree that is long-established in Israel, requires minimal water, is resistant to diseases and pests and is suited for a wide range of temperatures, including frosts and heatwaves. It grows in all kinds of soil, one of the only that is also fine in sandy, saline and chalky types. Thanks to its versatility, D. sissoo has been used widely from the beginning of the Yishuv for many years.

But over time, the tendencies for branches’ breaking or drying out have multiplied. Many trees have lost their vital appearance and look rather sad, to the point of degeneration and death. This phenomenon deterred and significantly reduced its continued use, and the tree that used to be a symbol of strength, liveliness and renewal became image-wise a problematic and not-recommended tree.

Against the backdrop of the cessation using D. sissoo as a street tree, beautiful and very successful specimens began to stand out in private gardens, and even here and there among the old trees in public spaces. It turns out that the common factor among the successful individuals was just the manner of their care. Those that were methodically designed in a controlled manner from their early years did not tend to break like others. Trimming that created a balanced frame and prevented acute branch angles created the proper design. Regular watering, even if not very much in quantity, prevented drying out. It was found that urban infrastructure works damaged the roots of many of the trees, which caused their decay. It was also found that injuries to D. sissoo’s roots caused the phenomenon of offshoots that grew without control into trees of their own. Understanding this led to the proper care to prevent it.

Now it is clear to us that with optimal treating from the very beginning, we can reach an excellent result with ideal properties for a street tree! There is a sweeping lesson for us here. Another lesson is this: those that were not cared for properly in urban spaces will never perform as they should. And in every aspect – both economic and functional – it’s worth it to replace them with new trees. Of course, we do not underestimate the nostalgia and value of very old trees. And from this perspective, we recommend creating a new point of reference. In our vision, one day the city streets will be graced with beautiful trees with an amazing presence and with a great and ancient sentimental value.

Additional articles:

Trees’ limitations – how to choose the right tree

Evergreens as street trees in Israel