The pad seems to be having some downtime just now, so two biodegradeable glues for example:

Synthetic: PVA
Animal-derived: Collagen/Hide Glue (oh noes, watch out for the PETA's!)

Both will be damaged by water, so you need to coat your joints in something like linseed oil.

Some text copy-pasted from that last wiki:

"Properties

The significant disadvantages of hide glue – its thermal limitations,
short open time, and vulnerability to micro-organisms – are offset by
several advantages. Hide glue joints are reversible and repairable.
Recently glued joints will release easily with the application of heat
and steam. Hide glue sticks to itself, so the repairer can apply new
hide glue to the joint and reclamp it. In contrast, PVA glues do not
adhere to themselves once they are cured, so a successful repair
requires removal of the old glue first – which usually requires removing
some of the material being glued.

Hide glue creates a somewhat brittle joint, so a strong shock will
often cause a very clean break along the joint. In contrast, a joint
glued with PVA will usually break the surrounding material, creating an
irregular, difficult to repair break. This brittleness is taken
advantage of by instrument makers. For example, instruments in the violin
family require periodic disassembly for repairs and maintenance. The
top of a violin is easily removed by prying a palette knife between the
top and ribs, and running it all around the joint. The brittleness
allows the top to be removed, often without significant damage to the
wood. Regluing the top only requires applying new hot hide glue to the
joint. If the violin top were glued on with PVA glue, removing the top
would require heat and steam to disassemble the joint (causing damage to
the varnish), then wood would have to be removed from the joint to
ensure no cured PVA glue was remaining before regluing the top.

Hide glue also functions as its own clamp. Once the glue begins to
gel, it pulls the joint together. Violin makers may glue the center
seams of top and back plates together using a rubbed joint rather than using clamps.
This technique involves coating half of the joint with hot hide glue,
and then rubbing the other half against the joint until the hide glue
starts to gel, at which point the glue becomes tacky. At this point the
plate is set aside without clamps, and the hide glue pulls the joint
together as it hardens.

Hide glue regains its working properties after cooling if it is
reheated. This property can be used when the glue's open time does not
allow the joint to be glued normally. For example, a cello maker may not
be able to glue and clamp a top to the instrument's ribs in the short
one minute open time available. Instead, the builder will lay a bead of
glue along the ribs, and allow it to cool. The top is then clamped to
the ribs. Moving a few inches at a time, the maker inserts a heated
palette knife into the joint, heating the glue. When the glue is
liquefied, the palette knife is removed, and the glue cools, creating a
bond. A similar process can be used to glue veneers to a substrate. The
veneer and/or the substrate is coated with hot hide glue. Once the glue
is cold, the veneer is positioned on the substrate. A hot object such as
a clothes iron is applied to the veneer, liquefying the underlying
glue. When the iron is removed, the glue cools, bonding the veneer to
the substrate.

Hide glue joints do not creep under loads. PVA glues create plastic
joints, which will creep over time if heavy loads are applied to them.

Hide glue is supplied in many different gram strengths,
each suited to specific applications. Instrument and cabinet builders
will use a range from 120 to 200 gram strength. Some hide glues are sold
without the gram strength specified. Experienced users avoid this glue
as the glue may be too weak or strong for the expected application." - Inline citations desperately needed.