Overall tree form is influenced by three factors: genetics, site conditions, and environmental events. The first tree visited, the Dawn redwood (Metasequoia glyptostroboides), became a prime example of strong genetics leading to an excurrrent growth habit: a tree with a central leader trunk all the way to the top, growing in an open site with plenty of light. In addition, the Magnolia acuminata found right outside the main gates became the best example of genetics leading to a decurrent growth habit, where a tree develops a more rounded form with multiple secondary trunks originating from the trunk, and also growing in a relatively open site with plenty of light. However, when site conditions are poor, a slope and shade for example, the same Magnolia acuminata will develop a very different growth habit.
For the next hour and a half, Andrew led teachers to 12 tree stops along Meadow Road towards the ponds. Each stop illustrated a different factor influencing that tree’s architecture: a hurricane event leading to a leaning trunk and exposed roots growing in the opposite direction from the lean, as in Acer mono; excessive waterlogging leading to the development of knees in the Bald cypress (Taxodium distichum ‘Pendens’); or a tree responding to internal phototropism, as in Kentucky coffee tree (Gymnocladus dioicus). At every stop there were exclamations of surprise and wonder, and lots of furious sketching in an attempt to capture the true essence of each tree.
The keeping of a science or nature journal was discussed upon the teachers’ return to the lecture hall. In order to help children connect with nature and develop appreciation and wonder about the natural world, regular journaling experiences need to be made available in the classroom. This can be done by bringing the outdoors in and placing plant specimens in a discovery table for sketching, or going outside for a focused exploration and inquiry. Gesture sketching is but one simple and quick way to get children to develop stronger observation skills, even with winter approaching. As all arborists know, now is the best season to really learn about trees!
Join Arboretum for Educators on January 7, 2017 for Tree Study Part 2: Reading Twigs.