property Items.CellForeColor([Item as Variant], [ColIndex as Variant]) as Color

Retrieves or sets the cell's foreground color.

TypeDescription
Item as Variant A long expression that indicates the item's handle.
ColIndex as Variant A long expression that indicates the column's index, a string expression that indicates the column's caption or the column's key.
Color A color expression that indicates the cell's foreground color.

The CellForeColor property identifies the cell's foreground color. Use the ClearCellForeColor property to clear the cell's foreground color. Use the ItemForeColor property to specify the the item's foreground color. Use the Def(exCellForeColor) property to specify the foreground color for all cells in the column. The HTML colors are not applied if the item is selected. Use the SelectedItem property to specify whether an item is selected or unselected. Use the ConditionalFormats method to apply formats to a cell or range of cells, and have that formatting change depending on the value of the cell or the value of a formula.

For instance, the following VB code changes the left top cell of your control: Tree1.Items.CellForeColor(Tree1.Items(0), 0) = vbBlue 

In VB.NET or C# you require the following functions until the .NET framework will provide:

You can use the following VB.NET function:
     Shared Function ToUInt32(ByVal c As Color) As UInt32
         Dim i As Long
	 i = c.R
	 i = i + 256 * c.G
	 i = i + 256 * 256 * c.B
	 ToUInt32 = Convert.ToUInt32(i)
     End Function 
You can use the following C# function:
private UInt32 ToUInt32(Color c)
{
	long i;
	i = c.R;
	i = i + 256 * c.G;
	i = i + 256 * 256 * c.B;
	return Convert.ToUInt32(i);
}

The following C# sample changes the foreground color for the focused cell:

axTree1.Items.set_CellForeColor(axTree1.Items.FocusItem, 0, ToUInt32(Color.Red) );

The following VB.NET sample changes the foreground color for the focused cell:

With AxTree1.Items
    .CellForeColor(.FocusItem, 0) = ToUInt32(Color.Red)
End With

The following C++ sample changes the foreground color for the focused cell:

#include "Items.h"
CItems items = m_tree.GetItems();
items.SetCellForeColor( COleVariant( items.GetFocusItem() ), COleVariant( (long)0 ), RGB(255,0,0) );

The following VFP sample changes the foreground color for the focused cell:

with thisform.Tree1.Items
	.DefaultItem = .FocusItem
	.CellForeColor( 0, 0 ) = RGB(255,0,0)
endwith

Note: A cell is the intersection of an item with a column. All properties that has an Item and a ColIndex parameters are referring to a cell. The Item parameter represents the handle of an item, and the ColIndex parameter indicates an index ( a numerical value, see Column.Index property ) of a column , the column's caption ( a string value, see Column.Caption property ), or a handle to a cell. Here's few hints how to use properties with Item and ColIndex parameters:

Tree1.Items.CellBold(, Tree1.Items.ItemCell(Tree1.Items(0), 0)) = True
Tree1.Items.CellBold(Tree1.Items(0), 0) = True
Tree1.Items.CellBold(Tree1.Items(0), "ColumnName") = True