First Published on February 25, 2015
I still want to know. A small chunk of knowledge imparted in an agronomy course at West Virginia University somewhere in mid 1960s has stuck with me ever since. I remember my wrong answer during discussion in lecture and I remember correctly answering a subsequent test question.
Question concerned photosynthesis, the process whereby plants take carbon dioxide from the air and release oxygen using sunlight for energy. Specifically the argument was whether greater photosynthesis took place in an acre of grass or an acre of trees. I pictured great tall maples and oaks and pines and guessed in lecture that an acre of trees would win hands down. Our textbook and professor said no. Grass wins.
A good thick stand of grass as in pasture or forage production has more photosynthesizing leaf surface per acre than does an acre of maples or pines. All those blades of grass added together do more work than all the leaves on trees. All the blades of grass in an acre generally have more light exposure surface than all the leaves on trees.
I wonder about this relationship every time I read or hear news stories about deforestation or simply planting trees to aid in removal of “greenhouse gasses”. Should we be advocating replacing inefficient trees with wholesome grasses? Grasses which are largely unfit for human consumption, but can be converted into red meat protein by animals which can consume and convert grasses wonderfully.
Trees furnish little food for consumption by humans or other organisms we normally eat. In a good year we can harvest palatable nuts, berries and acorns from a few species, but I’ve found those occasions rare and undependable. Squirrels, deer, perhaps birds, cattle and insects prefer acorns or berries when they are plentiful, but those tree foods are unavailable to humans in dependable, meaningful quantities unless we eat the proteins into which they are converted by animals.
New diet guidelines published last week by US Departments of Agriculture and/or Health and Human Services advocate less meat, more veggies. Arguments over organic versus conventional production notwithstanding, all that garden food we are supposed to be eating must come from soil disturbed to remove both grass and trees, then fertilized by either formulated or natural fertilizers. Any slight amount of that fertilizer in excess to plant growth requirements will remain in disturbed soil and is thus subject to faster erosion into nearby waterways.
A chunk of the five hundred plus page report on diet was devoted to recommended changes compatible with modern notions of climate change. We’ve heard arguments about how much effect on our environment cow farts have. According to modern science such production of greenhouse gasses by ruminant animals as cows, sheep and goats contribute to global warming through byproduct production of methane, a byproduct of ruminant breakdown of forages. This greenhouse gas escapes through both farts and belches in quantities much larger than those from humans.
At any rate, we can’t eat the trees or the grass because they are unsuitable for digestion through simple stomachs such as humans have. If we remove either to make room for soil preparation and sunlight access for cultivated vegetation, we are cutting down on natural, normal photosynthesis which cleans carbon dioxide from our atmosphere. Breaking soil’s natural cover also leads to increased erosion.
I’m not sure how I got into such a convoluted mixed up mess with this column, but I did. Might be an example of what happens when government tries to mix science with politics. Best advice I have is plant more grass and go with Chick-fil-A’s cow promoting “EAT MOR CHIKIN”.
