4043 Green Cross Code by Dipper

This was the 7th of Dipper’s Listener crosswords, all of which have an amusing gardening theme. In his arboretum words clashed and the letters remaining from down and across entries spelled the name of a tree. This had to be marked with a green cross. The preamble read, “Unfortunately, five of the trees have been attacked by insects, which have stripped the bark from each. However, the pieces of bark have been grafted together to form another tree, PALISANDER.” These trees were missing the first and last letters, which made the puzzle more difficult.
The trees were:
1a 2d Alder, 11a 5d (d)eoda(r), 15a 12d (a)lo(e), 16a 7d shea, 19a 1d aspen, 19a 14d mango, 24a 25d sapan, 32a 28d (p)ip(a), 33a 27d (a)lyss(a), 36a 31d palm, 35d 38a elder, 39a 23d (s)ouar(i), 39a 34d tilia and 41a 18d teak.

The initial letters of extra words in clues spelled the names of insecticides which would be an aid to Dipper in preserving the trees, DIAMETHOATE, BENOMYL, PYRETHROID, MALATHION and CARBARYL.

Extra words in clues are shown in []

Across
1 Move diagonally about high track by start of climb - wrong [decision] for this type of rock (9)
CALC-SINTER CATER (to move diagonally) containing L (track) + C(limb) + SIN
10 Radical surgery for malady, wanting [immediate] advantage (4)
AMYL Anagram MALADY less AD (advantage)
11 Justify disastrous raid near [Munich] (7)
DARRAINE Anagram RAID NEAR
13 Pardon me whirling into [Elgar's] score (5)
REMIT ME reversed in RIT
15 Diagram depicting line in [trapezium] at the right place (4)
PLAT L (line) in PAT
16 [Heptarchy] regularly varied feudal tax (3)
AID even letters in vArIeD
17 [Organist] is dull interlude in Hindu festival songs (9)
MELISMATA IS MAT in MELA
19 Indian soldier hiding northern rabble in [abandoned] fort (5)
PENTAGON N + TAG (rabble) in PEON
21 Force having flanks decimated in [tactical] operations (4)
URES (d)URES(s)
22 Badger runs away [eating] fish (3)
IDE (r)IDE less R (runs)
24 Royals in desperate straits when [besieged] (8)
TSARITAS Anagram STRAITS + AS (when)
26 [Especially] in Iran, Indian food suitable for Muslim feast (8, two words)
ID AL-FITR DAL + FIT (suitable) in IR (Iran)
29 [Not] without a second opinion (3)
BET BETA (second) less A
30 An [obvious] beginning to calculation concerning amount of land (4)
ACRE A + C(alculation) + RE (concerning)
32 Ignoring saint, animist and priest create a [monstrous] heathen (5)
PAINIM Anagram ANIMIST + P (priest) less ST
33 Becoming concealed, [yellowhammers] can settle undisturbed. Not (9)
LATESCENT
36 Odds against rare [leghorn] at first cock fight (3)
SPAR SP (starting price = odds) + A (against) + R(are)
37 Depression [prevalent] among single Norwegians (4)
GLEN Hidden
38 Alcohol bolsters endless [youths] in disorder (5)
STEROL Anagram (b)OLSTER(s)
39 Lacking energy, I replace it badly as component of [rustproof] steel (7)
PEARLITIC  Anagram I REPLACE IT less E (energy)
40 Mining engineer [explores] ridge over hill (4)
MESA ME + AS reversed
41 Heavy drug user is freed after medication in express [treatment] (9)
SPEEDFREAK Anagram FREED in SPEAK
 
Down
1 Adapted tooth in migrating Asian caracals, lacking all [healthy] calcium (9)
CARNASSIAL Anagram ASIAN CARACALS less ALL Ca
2 [Reason] beetle was active around excited termites without it (7)
DERMESTID Anagram TERMITES less IT in DID
3 [Ornate] moulding may start to crack badly (4)
CYMA Anagram MAY C(rack)
4 Among the characteristics of [Impressionism], take notice of design (6)
INTENT IN + TENT
5 Dress a lesion with a poultice initially, [delaying] morbid growth of tissue (8)
NEOPLASIA Anagram A LESION + A P(oultice)
6 Rubber [Michelin] tyres are partly retreads (6)
ERASER Hidden reversed
7 Break down in tears - he'd [aimed] to demoralise (8)
DISHEARTEN Anagram IN TEARS HE’D
8 On radio, you [leave] at the end of the day to become one (5)
UNITE Homophone YOU NIGHT
9 Fly found in baked [Alaska] (3)
KED Hidden
12 French king eliminating [treacherous] extremes of French right (3)
ROI (d)ROI(t)
14 Protected upper class succumbing to a cruel [hoax] (4)
IMMANE IMMUNE with U (upper-class) changing to A
18 Become [incredibly] like ... like ... almost like ... not like ... not half (9)
ASSIMILATE AS + SIMILA(r) + (ha)TE
20 Dock money - money I [otherwise] invested (8)
PATIENCE AT(coin) + I in PENCE (patience is a plant of the Dock family)
23 Referring to skin disease, doctor covers skill of American [nurses] (7)
DARTROUS ART in DR + O (of) US
25 Tights initially preferred by someone against [calico] stockings (7)
PANTIHOSE P(referred) + ANTI + HOSE
27 Cricketer making sly change in spin [attack] (6, two words)
FLY SLIP Anagram SLY in FLIP
28 Washed out from debilitating tiredness without changing set [routine] (6)
RINSED Anagram TIREDNESS less Anagram SET
29 Phone company including something to fasten [broadband] cables (4)
BITT IT in BT (British Telecom)
31 Less stressful state [affecting] fifty per cent of sheep (5)
CALMER CAL (state of California) + MER(ino)
34 I [recall] being taken in by that French woman (3)
CELIA I in CELA (that in French)
35 Meal prepared at one time. Order up after three helpings of melon [yoghurt] (4)
MELDER  MEL(on) + RED reversed
36 Watch has casing of pearly [lacquer] (3)
SPY ‘S (has) + P(earl)Y