A Tree object allows accessing individual trees (>4m height) in iLand via Javascript.

Note that using Javascript with individual trees can be slow.

Accessing a tree

Trees can be accessed via the Management object or TreeList list within ABE. The Management object provides tree and treeObject functions. Similarly, the TreeList includes tree and treeObject.

Reference vs object

iLand provides two distinct ways to access trees, namely as reference (to an internal object) or as a Javascript object. Access via reference is faster, but tree references can not be used for later access. See the example:

// load all trees of resource unit 0:
management.loadResourceUnit(0);
// access via reference: every call to the tree() functions modifies the reference:
var t1=management.tree(0); // the first tree (dbh=10)
var t2=management.tree(1); // the second tree (dbh=20)
console.log("Tree1: " + t1.dbh + ", Tree2: " + t2.dbh); // -> yields "Tree1: 20, Tree2: 20"!!!!

// access via object:
var t1=management.treeObject(0); // the first tree (dbh=10)
var t2=management.treeObject(1); // the second tree (dbh=20)
console.log("Tree1: " + t1.dbh + ", Tree2: " + t2.dbh); // -> yields "Tree1: 10, Tree2: 20"

// References are, however, useful for iterating over a list of trees:
var sum_dbh=0;
for (var i=0;i<management.count;++i)
    sum_dbh += management.tree(i).dbh;
console.log("Mean dbh: " + sum_dbh / management.count);