A study in growth

Striped maple (Acer pennsylvanicum) - the top of this year's growth

Looking out my window at the striped maple Sam & I transplanted last year made me want to start a long-term documentation project. The shrub caught my attention because it seems to be turning colors from the top down; this is the opposite of virtually everything else, which tends to turn from the top and outside working in and down. Maybe being a small shrub with a single stem of leaves makes this pattern so different? Maybe being in super low light conditions? 

Anyways, I've started various projects in the past, but this one will be easy - each year around Nov 1 (even marked it on my calendar) I'll take a quick photo of the striped maple to track its growth and branching pattern. I guess I probably should have put the marker just below the terminal bud, but below the first set of lateral buds will do. The other thing that will be neat to see is how the tape affects the color of the bark. Striped maple has photosynthetic bark, and my assumption is that it will drop its chlorophyll content and shift to a deeper red/purple color (as the older bark is). Though the tape isn't totally opaque, so we'll see about that too.

More little leaves

What: So in response to Ryan's comment about sugar maples being considerably later than their breathren to leaf out I set out to document some of the later-to-burst buds. A loose pattern I thought I found was that the later species to bud out seem to be the ones that are more shade tolerant. But my sample is too small to make anything other than a very gross generalization (and probably not that correct). I also didn't notice whether or not there's a difference between individuals in the canopy and individuals in the understory. I couldn't find great data on the order of when species leaf out (Project Bud Bursts data set isn't that great) so looks like I'll have to keep investigating.

I know that there is variation within a population due to small-scale climatic features. In the posting on dandelions I described finding dandelions that had gone to seed earliest in south-facing spots adjacent to buildings or rocks. Trees in similar warm areas tend to leaf out earlier. I followed up on the shade-tolerance piece and didn't find a whole lot pertinent to leafing out. It is pretty well established that a woody species' shade tolerance is most relevant in the seedling/sapling stages. The following table is condensed from Humbert et al.'s 2007 paper "A shade tolerance index for common understory species of northeastern North America". It gives ranks each species from 1-9, with 9 being the least tolerant of shade and 1 being the best, an X means that it has a wide range of tolerances. The real table has more trees, lots of herbaceous plants and even some mosses and liverworts.

Latin name	Common name	Shade tolerance index
Abies balsamea	Balsam fir	3
Acer pensylvanicum	Striped maple	3
Acer rubrum	Red maple	5
Acer saccharum	Sugar maple	4
Acer spicatum	Mtn maple	5
Alnus incana ssp. rugosa	Speckled alder	7
Betula alleghaniensis	Yellow birch	5
Betula papyrifera	White birch	7
Comptonia peregrina	Sweet fern	7
Cornus alternifolia	Alt leaf dogwood	4
Cornus canadensis	Bunchberry	X
Corylus cornuta	Witch hazel	4
Fagus grandifolia	American beech	2
Fraxinus nigra	Black ash	5
Larix laricina	Tamarack	9
Ledum groenlandicum	Bog Labrador tea	7
Lonicera canadensis	Fly honeysuckle	X
Myrica gale	Sweetgale	8
Ostrya virginiana	Hophornbeam	X
Picea glauca	White spruce	4
Picea mariana	Black spruce	X
Pinus resinosa	Red pine	8
Pinus strobus	White pine	6
Populus balsamifera	Balsam poplar	9
Populus grandidentata	Big-tooth aspen	9
Populus tremuloides	Quaking aspen	9
Prunus pensylvanica	Pin cherry	9
Prunus serotina	Black cherry	8
Prunus virginiana	Chokecherry	X
Quercus rubra	Red oak	7
Salix discolor	American willow	8
Salix humilis	Prairie willow	9
Sambucus racemosa	Red elderberry	5
Taxus canadensis	Canada yew	2
Thuja occidentalis	White cedar	3
Tsuga canadensis	Hemlock	3
Ulmus americana	Elm	6
Vaccinium angustifolium	Lowbush blueberry	7

The other columns that I would like to see in here would be simple vs compound leaf, ring-porous vs diffuse porous, successionary stage, and dry vs wet habitat preference, freezing killing temperature, herbivore pressure, leaf drop date, flowering date, furthest north latitude, center of evolutionary group's range, among others. So it's a start, but for now mostly just pretty pictures and a cool table.