Two articles on Trees Sensing Danger

Do trees recognise danger? Do they hurt?

I heard a broadcaster, Ann Swithenbank on a weekly gardening programme at the beginning of February talking about her hatred of Bonsai .Ms Swithenbank felt that bonsai artists were torturing the trees and that they should be left alone to develop into a full size tree. Well everyone is entitled to their opinion, and despite many hundreds of thousands of enthusiasts worldwide, and despite the fact that growing small trees are part of some people’s national culture. MS Swithenbank happily ranted against the entire hobby.  Ms Swithenbank then went on to decry Bonsai growers who display their collection on Benches. I am not sure if this is much different from growing Pot plants on benches in a greenhouse or outside. Or perhaps growing any plant in a pot is offensive to some people. I am sure that this is the case. Well bonsai growers actually have a life and their dedication in the hobby can be just as interesting as any other part of the human need for hobbies and pastimes. Not according to Ms Swithenbank who has just stated that Bonsai growers are cruel. I do not see why this should be a valid point of view though. To prune and keep the shape is not a great deal of difference to mowing a lawn, pruning a hedge or any other technique to keep something in shape and to keep the plant healthy and full of vigour. 
 

I don’t think that the Japanese art of Bonsai, the Chinese art of Penjing , never mind the tray landscapes of Vietnam and the knowledge handed down over thousands of years from father to son and daughter should be so easily cast aside by someone in such a powerful position as a television and radio presenter. For Ms Swithenbank to damage the reputation of growers and enthusiasts all over the world is less than savoury. Ms Swithenbank is a well known and talented horticulturist so why she has chosen to attack a large segment of her admirers and denigrate an entire hobby is somewhat less than pleasant.#

A bonsai is grown, created, styled, developed and made into a stunning miniature representation of a mature tree. A bonsai can be grown from a seed or shaped from a larger collected tree. The collected tree is usually struggling as a living plant and ideal collected trees may have perhaps one or two living branches while the rest of the tree and perhaps part pf the trunk, being dead. These dead elements are shaped by a master into shapes that illustrate the struggle the tree has had in nature. . However, if the tree is not carefully put into excellent soil, has its buds nipped back, pruned and cut, the tree will not survive. After all whet is a dead tree but a dead tree.  
no more than six inches high

The size surprises some people with collected and grown trees being anywhere from a few inches to over 2 metres. In nature there re natural Bonsai, where the growth has been subjected to severe wind, damaging falls of snow, freezing temperatures or blistering sun. All depends on the country and climate of course. Left there, these trees would eventually expire. The bonsai grower carefully studies the tree, checks the root growth and after careful lifting, brings the ailing tree back to their new home.  Without the horticultural knowledge then the collected tree would inevitably die.

Collecting trees and shrubs has been part of horticultural knowledge gathering for centuries.  Based on that knowledge horticulturist have gained their extensive experience. Bonsai growers simply make a tree that they grow a very happy tree and as you can always see at an exhibition or in their gardens. A note to Ms Swithenbank: The RHS would not have supported this hobby by allowing the venerable Bonsai author and grower, Peter Chan to mount a wonderful permanent exhibition at Wisley if they actually agreed with Ms Swithenbank point of view. . Yes it is a point of view but some points of view should be kept very quiet if it offends a huge part of the society that Ms Swithenbank lives in. I reiterate that she is in a powerful position and should know better than to alienate her fans and the programmes fan base.

Craig Coussins.

Bonsai grower, author of five best selling books on Bonsai and a fan of Anne Swithenbank

Do trees sense danger?

The giant Sequoia Sequoiadendron Gigantium  will have cones on its branches for fifty years and more but only shed the seed if it feels threatened by fire, A common event in old woodlands. Indeed most trees when sensing danger in its environment start to conserve energy and  shed seed. Indeed when some species such as Larch, Larix Decidua, are threatened they will start to put on copious amounts of cone and the energy expended in that will probably kill it but not until the seed has a chance to disperse. There is a saying we have in English called ‘going to seed’. That means that when trees are stressed they will start to put on their seed making hats and go forth and multiply.

In Bonsai it is sometimes the season near that trees end game that we look for when collecting a tree from the wild,. The tree may well be very old, have a large trunk and a lot of dead brunches but with the one or two living branches but covered in cones or seed pods that we can decide if we can save it or let it go. If we save it then we have a natural tree with a lot of age and something that we as artists can work up to make a wonderful old looking tree. Its all part of the art of Bonsai.

So as a grower of nearly 40 years I can see that trees do have a sense of danger when threatened and they will protect their gene pool or species by ‘going to seed’.  Is that an instinct? In fact why should we not consider that trees have feelings? It may not be feelings that we as animals would recognise perhaps . In most cases plants that do seed will know when they are being stressed and they will be able to something about it. Is that instinctive? If it was a animal that we recognise we would say that was the case but for some reason we seem less able to accept that a plant can feel danger and do something about it.

Botanists at Rutgers University infected some tobacco plants with a virus. Within a few days, tobacco plants that were near the infected ones sensed the danger of the virus and then produced a chemical in their leaves that would protect themselves from the virus. The infected tobacco leaves gave off a chemical odour that the healthy leaves sensed, thus triggering their defensive mechanism. Plants, animals and humans can sense fear or danger through a fine sense of smell or odour detection. Some do it through sensing subtle vibrations. Finely tuned standard senses may explain some psychic powers certain people seem to have.

John Z. Kiss, Professor of Horticulture and now at Rutgers says: Plants rely on sophisticated mechanisms to interpret the constant bombardment of incoming signals so they can adjust their growth accordingly.

Kiss J.Z. 2006. Up, down, and all around: how plants sense and respond to environmental stimuli. Proceedings of the National Academy of Sciences (USA) 103: 829–830

Other sources include:

 http://www.school-for-champions.com/senses/fear.htm

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