BEYOND PSHB: Trees to plant

Combretum Molle

The best trees to plant are those that you know you will take care of. I have a friend who loves River Bushwillows and can’t stand the Karee. Needless to say, the bushwillows thrive under his care; the karees do not. I love both, the former for its majesty and the latter for its tree climbing friendliness. Both are in the Top Five Trees for Carbon Sequestration.

Theoretically you should be planting both.

The PSHB Challenge

However, when theory meets reality it is possible that the theory may have to be put aside. I have had to do so. Given my preferences I would plant all the big five for carbon sequestration. However, because the River Bushwillow has become a non-reproductive PSHB host be aware that it might become infested at some fututre date. Trees that are reproductive hosts to the PSHB are best avoided, unless you are an ardent fan and will invest in what it takes to care for it.

The jury is still out on how to do this.

When in these situations of uncertainty, I like to imagine what I would do if planting and not planting made the difference between extinction and survival of a species. If not planting would lead to extinction I would plant as many as possible using healthy seed from infested trees, or transplanting seedlings from under its canopy. My hope would be that these seeds and seedlings have improved their immunity and have adapted to PSHB as a known predator, i.e. they are now better able to resist it.

I would be sure to take great care of them by meeting their needs for water and nutritionIf any became infested, I would remove them immediately, turn them into biochar. And continue to plant seeds and transplant seedlings, creating a virtuous cycle of commitment to survival. I would plant them out after two years of growth when the seedlings are frost resistant.

Planting for micro-climates

Nonetheless, it makes no to me to plant trees that have this or that pleasing quality unless the ecological system or micro-climate is optimal for its growth. Or unless you are willing to create the desired micro-climate.

In my own narrow passage of a garden, in the Paterson Park wetland in Orange Grove, I have decided to plant Noltea Africana and River Indigo. These will be planted into the ground rather than in pots for they are small trees, have shallow root systems and should do well in these conditions.

Tree Planting List from Retreat at the Botanical Garden in Pretoria

In July I visited the SANBI offices in Pretoria. I had hoped that they would be able to take charge of an informed response to the PSHB infestation. They weren’t and aren’t. I used the opportunity to connect with the trees on the ridge. The following are the trees I was drawn to:

Ochna Pulchra

Ochna Pulchra

Cape Chestnut: http://pza.sanbi.org/calodendrum-capense
Magalies Plane: http://pza.sanbi.org/ochna-pretoriensis
Common Wild Elder: http://pza.sanbi.org/nuxia-congesta
Large-leaved Rock Fig: http://pza.sanbi.org/ficus-abutilifolia
Mountain Karee: http://pza.sanbi.org/searsia-leptodictya
Velvet Bushwillow: http://pza.sanbi.org/combretum-molle
Tree Wisteria: http://pza.sanbi.org/bolusanthus-speciosus
Peeling Plane: http://pza.sanbi.org/ochna-pulchra

These I will source or plant. You may want to do so too. Yet for diversity, and to meet your actual needs, I would suggest you do some research, my way or your way, or integrate the two…for I am a sangoma and some of these are to grow in traditional medicinal gardens!

It seems to me that nature works with us when we work with it; it provides what we need, even what we want, sometimes. All types of trees can be planted: endemic, indigenous, exotic when in urban spaces we live. Here we have room to experiment, to make mistakes and then to correct them.

It’s the natural forests that are best left alone, to mess with these is to mess on a massive scale. So, please let’s leave the Amazon alone. Let’s stop diminishing its significance by measuring carbon and carbon only for there is no way we can replicate the complexity of what took nature millions of years to produce.

Let’s leave all our natural forests alone, regardless of how large or small they are. Instead let’s make a concerted effort to plant what we need in our already urbanized spaces. It’s possible to do so. It’s even possible to finance it. All it requires are significant mindshifts.

And some careful consideration of water in the landscape. If we do this so many challenges to forests and food forests planting are reduced. Designing for climate change is well worth the effort:

Sources and Resources

List of PSHB reproductive and non-reproductive host trees: https://www.fabinet.up.ac.za/index.php/pshb

The Big Five Trees for Carbon Sequestration: http://www.blueblueearth.co.za/garbage/

Planting list recommended by Treeworks: https://www.sanbi.org/documents/tree-list-highveld-and-grassland-region/