new forest garden model

Exciting new ideas on forest garden potential in temperate zones - Scrub woodland as a new model for temperate forest gardens? read Chris Dixon:: http://www.permaculture-wales.org.uk/index.php/editorials

Most of california south of the Northern Forest and grasslands was chapparal, in south africa with the highest density of species in the world is Fynbos, Matorral in chile, Maquis in France and Kwongan in Southwest Australia are all high diversity mediterrnean scrub lands aswell but I believe they got that way through Human intervention i.e. fire and the environments dry hot summers and cool wet winters.

Eithier way scrublands give alot more oppritunity to mix in more traditional/typical annual crops while still reaching and maintaining a climax system of species.

is a woodland the same as a scrub land or is a scrub land less densly populated than a woodland?

I think form follows function.. for my zone 2 gardens I envision shrubby savanna shifting to woodland on northern edges, with herbaceous systems to the south.

There is no international consensus on veg classification in the research community..particularly when it comes to relative balance of shrub vs. grass/forb layer.  The words I have most commonly seen in physiognomic (structural) classification schemes are:

grassland/shrubland (minimal trees)
savanna (less than 20-30% canopy)
woodland (20-80% canopy)
forest (>80% canopy)

Another question is the scale of the observation (quadrat size..).... local patches may exceed 80% tree cover, but at the scale of an acre it might be a savanna...

There is a term in wetland classfication called scrub/shrub, which is wetland dominated by non-tree woody veg.

All these words overlap with local usage.  The best practice would be to reference the % canopy cover of vegetative layers.

A huge factor in natural vegetation is fire return interval, with a tipping point from grassland to shrubland being somewhere between 5 and 15 years.