measuring productivity in a forest

Hi, do you have an idea of how can be measure the productivity in a forest?


I was reading in a forest garden desing book that its a good idea to design a climax forest because they are more productive.
One characteristic of climax forest is that they have a lot of diversity.
Do you think that measuring diversity of a forest can be a way of measuring the productivity of a forest?
Climax forest has also complex structures , so measuring complexity in the structure can be another way of measuring productivity?
What do you think? which is the best way of measuring productivity?

You're starting this topic over again? Wasn't your last question discussed at length? The single most accurate measure of productivity is site index, which is simply an age/height measure of the forest trees.

no, before i asked about measuring healthiness not productivity.

Michael Qulek wrote:You're starting this topic over again? Wasn't your last question discussed at length? The single most accurate measure of productivity is site index, which is simply an age/height measure of the forest trees.

The book on forest gardening I read recently specifically said that "climax" forests are not the most productive, and that you get greater productivity at intermediate successional stages. It also questioned the whole concept of climax - basically this is an idea constructed by biologists that doesn't really work in the field over longer periods of time.

How are you defining "productivity"?

When i talk about productivity i mean production of food, im interested to measure a feature in a forest that can be related with the production of food.
Basically im interested in algorithmically desing forest gardens that can maximize the yields , maybe the calories produced?

Peter Ellis wrote:How are you defining "productivity"?

I just checked the book , edible forest garden 2 and i was wrong, it says we can have more productivity at mid sucession stages. That would mean that site index would not mean a good measure for productivity right?
Since age/height measure of trees in climax would be greated than mid-sucession stages but that would not mean more productivity.

I was checking also the book from howard odum called "environment, power and society" . He says the most maps of the world productivity are based on net production.
And net production is the difference between the photosynthsis and the concurrent consumption.
With production he basically means photosynthesis production of organic products (organic matter and oxygen) .

Michael Qulek wrote:You're starting this topic over again? Wasn't your last question discussed at length? The single most accurate measure of productivity is site index, which is simply an age/height measure of the forest trees.

Even in a closed system, you'll have things constantly rotating about, depending on what sort of animals, plants, and labor you put into it. Woodland forestry is a tough enough science as it is, but the trees are fairly slow-growing things by comparison and only get harvested once per tree.

When you bring a food forest into it, that makes things far more complicated since you'd be expecting food harvests all year. At very least you'd have to compare the amount of calories produced to the nutrients lost. How much biomass/organic matter has been added by the trees. Check the average Brix levels of the produce as an estimate of whether microbial life has increased or been reduced, etc...

Unfortunately there's no way to cross-reference all that to a certain standard, but having the information around will give you an idea of what's going on. You'd need a massive amount of criteria to algorithmically design a forest, though. Far more than just heath and production.

Odum says that early grow stages of forest has high net production and small respiration .
The later stage has greater gross production and respiration and very low net production .
The rate of net production peaks first then biomass and finally diversity.

Gross production is the first step in transforming solar energy into chemical prtential energy. Measuring gross production directly is difficult because products made by photosynthesis are being used up by thge plants respiration processes at the same time.

Ronaldo Montoya wrote:What do you think? which is the best way of measuring productivity?

Calories of edible human food harvested per acre... If the food can't be harvested and eaten then I believe that it wasn't a food crop. If the forest produces a flush of blackberries that are eaten by starlings that then proceed to fly away, then the forest didn't produce a crop of blackberries, it only captured some dark purple manure which is not human food. Hard to tell if the starlings gave as much as they took.

Or if you want to get fancy:
Calories of edible human food harvested per acre minus calories of fossil fuels used in production.

Measuring protein harvested per acre might be an even better measurement, because protein seems to be more of a limiting nutrient in human nutrition than carbohydrates, fat, or calories.

But that doesn't take into account the other productivity of a forest: Wood, fibre, ecosystem services, soil conservation, sacramental services, etc...