Weight of a tree with branches

[Fossi]

Hello,

I would like to start an arborist business in southern Chile.  Since a while I own a truck with a Palfinger PK29002 F crane, which is great to lift and transport logs. Larger branches I cut for firewood. But I am also thinking of buying a chipper for the smaller stuff and then I would need something to transport the chipped material. But how big does such a trailer or truck have to be? So I was wondering how much volume and weight a chipped tree crown would yield or how to calculate or estimate the weight of a tree crown. There are pretty handy formulas and calculators for stem weight as long as the stem is somewhat regular and also for firewood. But I could not find anything for calculating branch weight or the weight of the entire crown. Actually this would be handy for any arborist anyway to calculate/estimate branch weight, for rigging purposes. I know, most arborists know from experience how much they can put on the line, but isn't there a formula or trick to estimate the weight? I was also thinking about situations where I might need to crane out parts of the tree. In these cases it would be crucial to have a good estimate about the weight of the piece if you do not want to risk the crane to fall over once the part is cut and is only supported by the crane. So does anyone know of a formula, rule of thumb, chart or anything else that would help to estimate the weight of larger green branches, tree crowns or entire trees? I know this is tricky, because it depends on the species, the growth form and the season/foliage. But there are charts and formulas for stems that take several parameters into account, so I would think it should also be possible for the green part. And how much chip volume do I get from a tree crown?

Edited October 25, 2021 by Fossi

[UnderTheRadars]

Sorry I can’t help, I’m just following this post as interested in finding out 

[Retired Climber]

You'd need a lot of data. I was always surprised how much heavier a truck full of Yew was, compared to most other things. 

Season also plays quite a part. 

No 2 trees are the same. 

The main thing to remember is if you use a transit size truck, unless you felled and chipped a bonsai tree, you are over weight. 

[Fossi]

Hi Retired Climber,

I am fully aware of the fact that it depends on several factors. Nevertheless the weight of a tree can only vary within certain bounderies. It would already be helpfull to know these bounderies. E.g. I would guess that an oak tree branch with a certain diameter in mid summer with maximum foliage will generally not exceed a certain branchlets and foliage weight. In winter without any leafs and with minimum water this would mark the lower limit. And for an entirely healthy tree of a given species and with a certain stem diameter I would guess there is also an upper weight limit. People calculate so many useless things, I would bet this has also been calculated somewhere by someone, wouldn't you? Concerning the truck overload, with a trailer or a second truck I would distribute the weight onto two vehicles, stems on my crane truck and chips on the other. I hoped this would do in most cases...

Edited October 26, 2021 by Fossi
gramatical error

[Mick Dempsey]

Too many variables, you’re wasting your time.

[rapalaman]

2 hours ago, Mick Dempsey said:

Too many variables, you’re wasting your time.

Spot on Mick

[kevinjohnsonmbe]

4 hours ago, Mick Dempsey said:

Too many variables, you’re wasting your time.

Complete waste of time and effort to try and achieve a data output which will vary so wildly from 1 task to the next that it will be completely useless. 
 

Load capacity on your available vehicles is all you need to know - that and when to ignore it. 
 

Then work out (through experience) how it handles. 
 

Then work out which routes / roads you can ignore load capacity because there are no Rozzers. 
 

There are occasions when complex theoretical data are useful.....  this ain’t one of them. 

[Fossi]

Hi Kevin,

I agree, for the transport question it would be a waste of time if I already had the vehicle to transport the chipped material. But exactly this is the point: I want to plan which sized vehicle would be the most usefull. Of course I could buy the biggest truck available to be on the safe side, but if I then would go half empty in most cases it would be a waste of money and fuel and it is unconfortable to drive big trucks. On the other hand if my truck or trailer would be so small that I have to do several trips for most jobs, and job sites can be >100 of kilometers away, this would be a waste as well.  This is point 1. The second point is weight estimate for craning puroses. Of course I could always go so small that even without having a slight idea how much a branch or tree top weighs the crane would not tip for sure. But this is inefficient, because there would be many cases where I would crane two or more pieces where one would have done without problems. And there is no way to find out by trying. The problem with cases where exceeding the limit would be fatal is that there is no recomendable empiric way to find out where the limit is. This is where modelling and calculations come in handy. There is helicopter logging and I cannot imagine that they simple tried out if the heli still can hold the cut tree and did not do any estimates of weight beforehand. I already thought about buying a crane scale with which I could weigh every load and this way get experience about the actual branch weights. But if I already knew the rough range it would safe months if not years of tries.  

Well, from the comments so far I conclude that I am not the only one who does not know about a practical way to estimate branch and crown weight and chip volume. Still, I cannot believe that this has not been tried so far. I know that there are calculations on biomass production of trees in the context of CO2 fixation, to calculate the climate benefit for certain forest types. But I do not know if this is working on the tree or on the forest level. Anyway, for this calculation I would assume that foliage and wood weight of certain species has been calculated. Maybe the span is really so big that for this purpose only the average makes sense but I really would like to see such statistics/calculations before I discard them for my aplications. 

[drinksloe]

A decent eye and plenty of experience coupled with some guess work and a bit of luck.

 

Even u coming from chile, tree species could be totally different and even similar species may grow completely differently due to ur climate, so any calculations from uk would be useless.

I imagine even in uk comparing an 'average' hard wood would vary massively from south england to north scotland or as u gain altitude..

 

Most bosses will learn while dragging brash or starting to climb as a worker a tree of that size takes X amount of transit tippers/trailers full of chip.

And probably learn more when they hear there experienced bosses moaning about jobs as even with experienced priced them badly as under estimated the ammount of chip in the job