Vol. 1&2 of my pen and ink workbook series focuses on drawing tree trunks, roots, tree foliage and landscapes based on them. With step by step intuitive explanation of stroke and techniques used along with fully illustrated examples and hand on exercises, this workbook will get you starting drawing pleasing pen and ink landscapes in no time. Pl. scroll below for a quick video overview (2 min.)
Also check out the other workbooks in the series.