Several weeks later, the fungi and bacteria have begun to infect the wood. A diagrammatic view shows the ray cells infected, and a resin pocket forming as the walls of the surrounding cells begin to dissolve. (fig. 115)	A blue-stain fungus and many bacteria in ray cells. The bacteria are clustered near the pits. The microorganisms begin to digest the cell contents, and blue stain results. (fig.116)
Figure 115	Figure 116

Figure 117

Broken and dying branches are some of the most common infections courts for microorganisms. large branch stubs on trees (that have heartwood) expose heartwood. (fig.117)

A closer view of a branch stub on an old oak. (fig.118)	When the stub surface is sawn smooth, this is the view of the old branch with central heartwood. (fig. 119)
Figure 118	Figure 119

Figure 120

A closer view of the heartwood near the branch center shows the vessels plugged with tyloses. (fig. 120)

Figure 121

A closer view of the sapwood shows the open vessels oozing moisture. (fig. 121)

The vessels appear as large tunnels or caves at this magnification. (fig. 122)

Figure 122

The ordered pattern of fibers surrounding the vessels is shown here. Each microscopic droplet of moisture could be the site or battleground for intense competition by many groups of different microorganisms. (fig. 123)
	Figure 123
After several weeks the fungi and bacteria invade. The small dots are the bacteria. The cells have been injured or killed, so invasion is an easy matter for the microorganisms. They reproduce rapidly and begin to interact with the tree. (fig. 124)
	Figure 124