Selfjoin Problem With Tree Structure

I have the following table
Memberid int
submemberid int

example
MemberId SubMemberId

1 2
2 3
1 4
3 5
2 6
7 8

Each member may supervise more than one member under him (whom I call submember)
and then each sub member may also supervise more than one member under him
I need to be able to select a specific member for example whose id is 1 and consequently all his sub members should be selected whose also all submembers should be selected and so
on
I do not know how to do this here is my trial:



ALTER Procedure dbo.MemberReports;1

@MemberMaskId nvarchar(8)


As
SET NOCOUNT ON
Begin
Declare @Exists Int -- Return Value

-- Select * from MembersTree where MemberId = @memId or MemberId = subMemberId


SELECT
MembersTree.memberid,
MembersTree.submemberid,
MembersTree1.memberid
FROM
MembersTree
INNER JOIN
MembersTree MembersTree1
ON MembersTree.Submemberid
= MembersTree1.memberid

WHERE
MembersTree.MemberId = @memId

If @@rowcount = 0 -- No Record returned
Select @Exists = 0
Else
Select @Exists = 1
Return @Exists

End

Please help,
Thanks