these links are useful

https://onlinelibrary.wiley.com/doi/pdf/10.1111/geb.12238

https://uanews.arizona.edu/.../size-and-age-of-plants-impact-their-pro...

regards

One of the main focuses of the forestry discipline is optimizing the felling age (rotation period).

There are similar age one species, mixed age one species and multiple species forest in both categories (it is a better description than natural or man made from productivity perspective).

The mixed age multiple species ('natural') forest productivity is the same for centuries. Even if you extract timber (up to a level) it remain the same. There is no more net carbon sequestration, the sequestered carbon and the released from decomposition are in balance (except in extremely colt climate).

In the case of single age forests, the growth curve is species specific, but usually start slow (from biomass perspective) accelerates and reach the full potential when all area is covered by the trees' crowns. From that point, until the trees health affected by aging, the yearly growth is approximately the same. The highest economic value is somewhat later than the peak of the mass since higher diameter timber is more valuable. The thinning (earlier wood extraction from the forest) influences the growth curve (drop in mass the accelerating growth).

After the harvest, you leave around the 50% of the extracted biomass in the soil. The decomposition can be slower than the rotation period, so you accumulate soil carbon up to 3 rotation periods. If you use the extracted wood in durable products, you optimize the net sequestered carbon.

The decomposing trees are lost opportunities, you could use them for replacing fossil energy.

I do not want to refer an article, because it is an entire discipline.

interesting question

Following the answers.

Intetesting

Thank you Robert Istvan Radics.

Very stimulating question

I think, for good efficiency it will be better to replace old trees with new fresh trees.

Undertaking Farm forestry for Industrial use is also a systematic way to meet demand for forestry produce.

The size and age of plants has more of an impact on their productivity than temperature and precipitation, according to a landmark study. They show that variation in terrestrial ecosystems is characterized by a common mathematical relationship but that climate plays a relatively minor direct role. The results have important implications for models used to predict climate change effects on ecosystem function and worldwide food production.

Check the following link:

https://www.sciencedaily.com/releases/2014/07/140720204326.htm

Tree rotation(from seedling to maturity) varies from species to species and also variation may be dependent to geographical location. Another way of determining tree's age is by counting annual rings. Not all old trees need to be cut as the very main functions of Forest/trees are their ecological functions....yes of course at maturity trees do add very little or no increment (additional biomass) but however there are various types of forest...for instance trees in steep slopes are normally stand for a protection forest which is of paramount importance as regards to their ecological functions such as soil conservator, water conservator, wind barriers, shaders, nutrient recyclers among others.

Fast growing trees are known to be high water demanding species which need to be properly selected when they are to be used in forest plantation-

Forests are one of the most complex terrestrial ecosystems and need to be prudent while dealing with...it can be argued that their ecological function is much more important than their economic function, the latter which focuses on human wealth while the former focuses on the planet's wealth---as trees are also known to be the globe lung...so forest managers and other forest experts need to rethink well while dealing with trees which are autotrophs and moer importantly are primary producers for almost all terrestrial food chain....knowing trees rotation is esential if we are to focus on forest for economy....Not all trees are for cutting but however all dead trees may need to be replaced....this is my opinion and welcome all corrections as we are to share knowledge....

Very good question, dear prof. Nafees Mohammad!

I have not seen such studies. I will follow.

Informative discussion.

Dear prof. Nafees Mohammad,

Genuine question which need to be scientifically proven whether old trees have low ecological functions or not. Due to the fact that growth stages in old matured trees have already been completed,, yes i do think they have reduced ecological functions. However the very irreplaceable function of chlorophyll pigmented tree parts, especially the leaves, as regards to the manufacture of their own food need to be appreciated. It is more likely that trees do have their photosynthetic rate reduced with age but however they still purify the air and carry other ecological function. Once old trees be proven to perform low ecological function, great care need to be taken to replace them but keeping the very basic sustainable principle of clear-felling avoidance to protect soil from having texture and structure destroyed due to brutal exposure to sunlight and other climatic conditions....the proposed study will provide efficient tools to better manage forest,such precious complex ecosystems ,upon which multitude of life forms depends....including human life...

following

The importance of trees go beyond economic consideration or wealth creation. Removing trees for economic reasons just because they are old to me is not a perfect idea especially when such trees are located in ecologically fragile areas where they can still play some important ecological roles despite their age. What do you actually mean by 'old trees'? Note that a tree that is over 100 years can still be ecologically relevant. In conclusion, I think considerations for the removal of old trees should go beyond economic reasons to include other roles such trees play where they are situated. Warm regards.

According to the study conducted by Qinfeng Guo & Hai Ren "Under generally similar physical conditions plantations aged 0–80 years already had similar biomass but much higher productivity, and thus much higher carbon sequestration rates, than natural forests. Tree biomass, productivity and their above/below ground ratios showed stronger latitudinal and elevational trends in natural forests than in planted forests." { Qinfeng Guo & Hai Ren " Productivity as related to diversity and age in planted versus natural forests" GEB J. Volume23, Issue12, December 2014, Pages 1461-1471 (https://doi.org/10.1111/geb.12238)}

Also, this study is useful

Effects of stand age on net primary productivity of boreal black spruce forests in Ontario, Canada (http://www.cfs.nrcan.gc.ca/bookstore_pdfs/21005.pdf)

Very interesting question.