There are many things to consider when planting trees next to buildings and along roads or avenues. This is a non-exhaustive list of tree species that I recommend for our region (Auroville, India) in the typical laterite or black cotton soil. This is an evolving list.
General species selection criteria:
Not prone to structural failure
No dangerous fruit (falling risk-wise and also poisonous plants taken into account)
Ideally with interesting features (bark, leaves, flowers, shape, fruit etc…)
No buttress or superficial roots (surface roots that would disturb pavement, hinder traffic)
Little mess in terms of fruits, flowers, foliage (apart from fruit trees)
Important for local ecology
Large evergreen trees to be used as shade for houses or avenues
Yes, neem trees lose their leaves every year, sometimes multiple times but, if a tree ends up with dead leaves up in the canopy then there is a problem due to an external factor. Yes, neem dieback has been around for some time and some trees recover from it. All neem trees that I have inspected have been affected by this to some extent. Older trees, very young trees and trees in poor condition or environments will likely be the most affected.
In the image below is the tea mosquito (Helopeltis antonii)which is one way that the fungus (Phomopsis azadirachtae) is transimitted which then causes the specific neem dieback disease (scientific evidence below).
Generally, all trees can be vulnerable to drought, especially to prolonged drought. It depends on their condition and the extent of the drought. With regards to excessive rain, if the roots are submerged for an extended period, they will not get oxygen, so they won’t be able to sustain their system (they can’t burn sugars). This FAO document mentions drought and neems. It is how I eventually came to the conclusion that the neems will not be able to deal with this very well (but it is likely to be consisting of even more factors).
The succession of detrimental events is the usual course for the death of a tree. Unlike us, they are not programmed to die. So, if a tree is affected by a disease, it is then more susceptible to other diseases.
From what I understand (or think I understand) the C4 compost acts a positive environment for germination for the bacillus which then will merge with/inoculate the absorbing roots (which will also be prompted to grow due to the new richer environment, hence the combination). Then the Bacillus will induce systemic acquired resistance (which should help with the Phomopsis) along with potentially helping with uptake of water and nutrients through synergies with mycorrhizal fungi.
To give an idea of what could be affected, when surveying about half of Auroville excluding the “Greenbelt” (~2.5 square kilometres) Geomatics have recorded over 3000 neem trees. So there are potentially over 20,000 neem trees in Auroville.
Here is what has been achieved in Auroville, regarding treatment, so far (I am only involved in some of this):
Contributing financially (it costs about RS55 per tree just for the materials and we are all doing this for free) by using the temporary Auroville FS account for this: 253042
Letting me know if you have other methods which work
Inspecting the trees, plotting them and then monitoring them to see how the treatment is acting
I am happy to come by (locally) and explain, show, teach (can be part of a school or research project).
Please let me know if you treat trees somewhere so we can record it (to later check if it works as intended and get statistics. If you want to be involved in this aspect, that is also possible).
This is the first step in setting up a response to a potentially huge loss of neem trees. All networking and collaboration could be improved and should be and if you want to coordinate efforts, please do so as I do not need, or necessarily want, to be involved.
If you have any other ideas, please suggest them (especially if you want to do the legwork).
A presentation I gave providing a brief glimpse into the effects that trees have on our lives and surroundings in an urban setting.
Presentation starts at 3:30.
Recently, in urban settings, trees are being used more as green infrastructure providing ecosystem services rather than merely street furniture. This presentation illustrates some ways in which this applies.
This presentation uses examples from the U.S, the U.K. and from India, where I am based. It includes the positive and negative effects and ways to improve matters with existing trees as well as potential trees. It is based on experience and research from around the world.
This is relevant for architects, town planners, municipal corporations, engineers, landscapers and anybody interested in improving urban forests through arboriculture.
This seminar occurred on the 17th of February 2019 in Pune, India. It brought arboriculture to the table of planning and infrastructure in Indian cities. Tree consultants from India, the UK and Singapore presented to architects, landscapers, municipal corporations and other professional bodies involved with trees.
There were several good speakers with different experiences and backgrounds. They provided us with different views on current techniques and practices from around the world. It was a refreshing experience when arboriculture is currently rather rare in India.
Island Lescure, director and consulting arborist of Treescapes, was there to speak about the benefits and drawbacks of trees in urban spaces and how to improve matters. This is important as engineers and town planners need to be made aware of the importance trees can bring to improve social wellbeing, storm water management systems, energy savings and many other social, ecological and environmental aspects of our lives. Trees enhance our lives: this can even be worked out in a monetary way by using tools such as itreetools.org. But these trees need appropriate installation and management.
Our associate, Jonas Suchanek, executive and climbing arborist of TreeCare India, was also present to give a demonstration of safe climbing techniques used around the world. This evoked quite a bit of interest (as fit young men swinging around in trees usually do) to improve the safety and efficiency of staff members of various parties present who climb trees. The current method of climbing and working in trees is both very safe and efficient. Short training courses can be provided.
We hope to see more of these sorts of events in India in the future. This will bring awareness of trees to people and it will enable us to improve ourselves and share our experiences. For a first event, it was a great success!