20个暴利养殖项目中的银杏树财源滚滚的绿色巨人

银杏树的特点有哪些？它们是实生银杏，能够长成高达30米以上，胸径超过3米的巨木。在适宜的生态环境中，它们可以培育出直立、尖削度小且质地优良的用材。这些条件之一就是浙江省临安县西天日山上，那里的银杏不仅与金钱松等林木共存，而且由于土壤肥沃和疏松，它们能更快地发展，拥有十几米长且粗细均匀的主干。

90年后期生的成熟树高可达23-26米，每株平均材积约为1立方米，并仍处于高峰期。此外，即使在孤立或偏北（如辽宁）或偏南（如广东）的分布中，银杏也可能只在主干上分枝高度不足2米，其主干上下差异极大，这通常是由于植株生长受到多种因素限制而造成。这种状况虽然对生产优质木材不利，却有助于提高植株开花结实能力。

银杏树皮由带缘孔圆形管胞组成，其中部分薄壁细胞内含有显著红色的大粒草酸钙结晶，但其射线极淡弱，有明显年轮记号。它们具有较厚皮层，上面布满小菱形或椭圆形皮孔表皮呈条状或块状裂开，具有一定程度交叉斑纹。

silver birch tree bark is composed of round cell tubes with lenticels, and some thin-walled cells contain large crystals of calcium oxalate, which appear red under the microscope. The bark is relatively thick and has small diamond or oval-shaped pores on its surface, with a pattern of longitudinal or block-like cracks that show some degree of cross-hatching.

Silver birch trees have numerous hidden buds on their trunks. These buds can grow into short branches that sometimes bear flowers and seeds. Under certain conditions, these buds can swell to form raised lumps along the main branches, which are commonly known as "lumps" or "tree sap". The largest recorded lump was over 2 meters long and had a base diameter of more than 28 centimeters (in Guizhou). At the base of the trunk, these bumps expand horizontally to form swelling nodules called "chairs." Sometimes there are rows of rounded protuberances along the main trunk that are also formed by silver birch notochord growths but lack clear downward orientation.

The mechanism for forming these protrusions is still unclear but may be related to plant growth suppression. Silver birches produce both male and female reproductive structures in their trees but tend to produce more galls in females than males. This has led people to say: "Only when silver birches have grown galls and chairs can they bear fruit." However this statement lacks foundation - not only mature trees but even young seedlings can develop small nodules below ground if their root system is restricted or under specific conditions; conversely, mature silver birches do not necessarily produce galls as they enter fruiting phase either.

Therefore it would be worthwhile researching whether one could use difficulty in producing galls as an early indicator for assessing silver birch fruitfulness and other traits.