Western junipers (Juniperus occidentalis) are so ubiquitous here is Modoc County CA that it is never surprising to see one. However, one does wonder at all the junipers growing along fencelines, particularly between fields and pastures. Farmers and ranchers certainly do not plant them in cultivated areas. Yet most fencelines are lined with junipers of varying sizes and ages. These trees crowd against the fence and fenceposts and some even grow with branches surrounding the barbed wire.
Enter overwintering birds. Many species, particularly robins (Turdus migratorius) and Townsend’s solitaires (Myadestes townsendi), depend on juniper berries to survive through the winter. They eat the berries and then fly off to rest on fenceposts and wires, depositing the juniper seeds along the fenceline. The hard seeds with their fleshy covering are scarified (cut or soften the wall of a hard seed) as they pass through the birds’ digestive systems, ready to germinate once spring arrives. These seed-eating birds are the “Johnny Appleseeds” of junipers, scattering seeds along fencerows – a very efficient dispersal method for juniper trees.
With time more and more junipers germinate along the fenceline, and if not removed, grow to maturity. These attract and provide shelter for not only birds but small mammals such as rabbits, mice, voles and skunks. These new residents continue to bring not only juniper, but other grass, forb and shrub seeds to the fenceline. Eventually the fence itself might be almost totally surrounded by trees and shrubs. What was once a fence has become a hedgerow (row of trees or shrubs surrounding a field). This new hedgerow provides a habitat for many plant and animal species. Leonard and I encourage hedgerow thickets between many of our pastures and enjoy the wildlife they attract.
The junipers in the picture were planted by birds along one of the fences near our house. We are happy to have them there. The grass in the foreground is intermediate wheatgrass, which is usually grazed by livestock over the summer. However, this year there was so much precipitation and the grass grew so tall that we cut and made hay in that field – thus the short grass in front of the taller grass next to the fence. The mule deer love this field!