[Talk-us] misuse of the landuse=forest tag for national forests

stevea steveaOSM at softworkers.com
Sat May 11 23:27:26 UTC 2013

>Thanks a lot for your reply. I really appreciate you work for 
>updating the national forests in southern California.

Nice of you to say so.  I did get a lot of positive feedback from 
posters to talk-us saying something similar.  I have a lot of work to 
continue to do this with eastern, central and northern California, 
and that work is on hold for right now, but this is documented and I 
do intend to get to it.

>Before posting I already read the wiki pages you mentioned. For me 
>it seemed that there is still some dispute about how the tag 
>landuse=forest is used and there exist different approaches. What I 
>only learned now is that US National Forests are indeed used for 
>timber harvesting (and not only for forest protection) so I now 
>fully agree that the natural=wood tag is inappropriate.

I guessed as much, but wanted to make sure you had read our 
documentation wiki.  However, US National Forests, while they 
certainly DO allow for timber harvesting, also allow for, say, scrub 
harvesting, if in fact it is scrub rather than trees which exists in 
the FOREST land surrounded by the boundary of landuse=forest.  For 
example, I was recently camping at Bottcher's Gap Recreation Site in 
northern Los Padres National Forest and Lorenzo there (the "camp 
host," similar a ranger, but more like he collects fees and keeps 
order, but without a gun and a badge like a "full" ranger) told me 
that if I wished to collect wood for a campfire, I was perfectly free 
to do that, after all, it is a national forest owned by the public, 
which includes me.  While there certainly are a lot of trees in that 
area, scrub predominates.  What Lorenzo meant is that I could collect 
"wood" from (downed) trees and branches as well as (dead and downed) 
scrub, too.  In other words, a national forest is the boundaries 
inside of which forests, whether scrub or trees, is "managed forest 

>However, one thing which I still find strange is to tag large areas 
>of scrub (bushes without any trees) as landuse=forest. Somebody 
>using the map may be surprised when not finding any trees in a 
>region mapped as a forest.  [The parts of the Angeles National 
>forest that I have seen so far are dominated by scrub] For me using 
>the landuse=forest tag in this case seems to contradict the fact 
>that landuse=forest is supposed to describe woodland.

I am absolutely not surprised when I find no trees in a national 
forest.  These are huge areas which unrealistically can be expected 
to be solid, 100% trees.  Please don't confuse "land cover" with the 
political/jurisdictional and geographical definition of "inside the 
boundaries of a national forest."  A national forest frequently does 
have dense tree cover, but its land cover may be desert-like sand, 
scrub, trees, or even barren rock, among other things (marsh, 
mud...).  All of these types of land cover are found "within the 
national forest" and this is not a contradiction.

>In an ideally detailed map those parts would be marked as scrub. For 
>me it seems that what to do in the current situation is a question 
>of what to take as a default. Your point of view is marking 
>everything as landuse=forest and manually excluding scrub land. I 
>thought it would be better to only mark parts as forest which 
>clearly are woodland. Since your point of view seems to be the 
>standard practice right now, I agree that it is probably the best to 
>stick to it (although this means, imho, ignoring the conflicting 
>definitions of scrub and forest).

What I mark with USFS-published forest and wilderness boundaries are 
just that.  The (standard/mapnik) renderer makes these solid green, 
which you appear to be confusing with a visual semantic that means 
"this is all trees" which is most certainly is not.  Rather, it means 
"this is all national forest."

>Buy the way, what is rendered when a region is landuse=forest and 
>natural=scrub at the same time?

Scrub, I believe, but this is only what I think happens in mapnik. 
Other renderers may (and can, and maybe even should) do something 


You are welcome!


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