Tropical trees

[Jack-Arb aka Tiago Sinclair-Julio.]

Do trees in tropical jungles have annual rings?

I was in a lecture a few years ago when studying for my arb qualifications, cant remember how the conversation begun but someone said very comfidently "trees in the tropics dont have annual rings". Ever since I heard this I've had this in my head. Is it true or not do they have rings or not? Has anyone been fortunate enough to have been in the Amazon for example or has anyone heard the same thing?

 

Jack

[Sciadopitys]

In the tropical rain forest, relatively few species of trees, such as teak, have visible annual rings. The difference between wet and dry seasons for most trees is too subtle to make noticeable differences in the cell size and density between wet and dry seasonal growth.

[munkymadman]

i work in the tropics, looks like any other wood to me. they have rings but seem to be larger than european trees. maybe its different right in the rainforest

[Jack-Arb aka Tiago Sinclair-Julio.]

In the tropical rain forest, relatively few species of trees, such as teak, have visible annual rings. The difference between wet and dry seasons for most trees is too subtle to make noticeable differences in the cell size and density between wet and dry seasonal growth.

 

Cheers Sciadopitys,

 

So what you're saying is that most species dont have visible annual rings, and the reasons for this is the fact of not having seasons, or if they exist they are to subtle to interfere with the trees growth. In other words they dont become dormant during winter like in the North hemisphere, so because of this they grow all year round without showing the pattern of the seasons on the annual rings...

 

It sort of makes sense, but still would like to see this with own eyes. It seems so bizzare this idea.

 

jack

[Amelanchier]

In the tropical rain forest, relatively few species of trees, such as teak, have visible annual rings. The difference between wet and dry seasons for most trees is too subtle to make noticeable differences in the cell size and density between wet and dry seasonal growth.

 

There's the key.

No seasonal variation = no earlywood and latewood. Thats what annual rings are of course, cross sections through smaller denser vessels. If you don't need them, you don't grow them.

[rumination]

While it is true that some tropical tree species do not have distinct or noticeable growth rings, many others definitely do. However, because many tropical trees may put on more than one growth spurt per year it is not possible to calculate the age of the based on the number of rings it has.

 

My last job was working at a rainforest arboretum in Hawaii that has over 1000 tropical tree species, so I got to see the inside of a lot different trees.

 

As for seasons: some tropical areas definitely do have distinct seasons that influence tree growth, but instead of being delineated into warm/cold they are wet/dry. In wet/dry tropical forests the trees go into a definitive dormancy during the dry season and many of them will be deciduous (dropping their leaves).

[kevwrenn]

interesting one this.... not something i have any experience of... on a similar note, what happens about leaf loss and regrowth on decidous species??? do they have seasons or does it vary from tree to tree???