Empty categories (traces or other) are annotated in all the conjoined constituents.
Wh-trace in CP-ADV:
( (IP-MAT (NP-SBJ *pro*)
        (CP-ADV (WADVP-1 (WADV Quando))
                (IP-SUB (IP-SUB (ADVP *T*-1)
                 (NP-SBJ (PRO elas))
                 (VB-P-3P andam)
                 (PP (P a)
                   (IP-INF (VB piar))))
             (CONJP (CONJ e)
                 (IP-SUB (ADVP *T*-1)
                     (NP-SBJ *pro*)
                     (VB-P-3P andam)
                     (ADJP-SPR (Q muito) (ADJ-G-P alegres))))))
        (, ,)
       (VB *)
       (CP-THT (C que)
               (IP-SUB (NP-SBJ-2 *exp*)
                         (SR-P-3S é)
                         (NP-PRD-2 (D-F a) (ADJ-F boa) (N nova))))
        (. .)))
  [CORDIAL-SIN; ID PST09]

Wh-trace in CP-REL
(IP-MAT (NP-SBJ (D o)
         (N menino))
     (HV-D houve)
     (NP-ACC (N medo)
         (CP-THT (C que)
             (IP-SUB (IP-SUB (NP-SBJ (D-F-P as)
                         (N-P ondas)
                         (, ,)
                         (CP-REL (WNP-4 (WPRO que))
                             (IP-SUB (IP-SUB (NP-SBJ *T*-4)
                                     (ADJP (ADJP (ADV-R tam)
                                            (ADJ-F-P altas))
                                        (CONJP (CONJ e)
                                                                      (ADJP (ADV-R tam)
                                              (ADJ-F-P espantosas))))
                                                       (SR-D erão))
                                     (, ,)
                                 (CONJP (CONJ e)
                                     (IP-SUB (NP-SBJ *T*-4)
                                         (ADVP (ADV-R tam)
                                            (ADV bravamente))
                                         (VB-D ferião)
                                         (PP (P em@)
                                           (NP (D-F @a)
                                              (N terra))))))))
(WOCHWEL; ID JAR76,.8)
( (IP-MAT (NP-SBJ (NUM-F Duas)
(N-P naus)
(ADJ-F-P inglesas)
(PUNC ,)
(CP-REL (WNP-1 (WPRO que))
(IP-SUB (IP-SUB (NP-SBJ *T*-1)
(VB-D saÃram)
(PP (P d@)
(NP (D @o)
(N porto)
(PP (P de)
(NP (NPR Priamua))))))
(PUNC ,)
(CONJP (CONJ e)
(IP-SUB (NP-SBJ *T*-1)
(VB-D iam)
(PP (P para)
(NP (D o) (NPR Estreito))))))))
(PUNC ,)
(ADJP-SPR (N-P acossadas)
(PP (P de)
(NP (D-UM-F uma) (N tempestade))))
(VB-D arribaram)
(PP (P a)
(NP (D-F esta) (N cidade)))
(PUNC .))
(TYCHO BRAHE; ID G_001_PSD,30.443))

It must be noted that in conjoined relatives, WH-traces can display different syntactic functions.
( (IP-MAT (NP-SBJ (D-UM Um)
(PP (P d@)
(NP (D-P @os)
(ADJ-R-G-P maiores)
(N-P rigores)
(CP-REL (WNP-1 (WPRO que))
(IP-SUB (NP-ACC *T*-1)
(TR-P tem)
(NP-SBJ (D-F a) (N morte)))))))
(PUNC ,)
(SR-P é)
(IP-INF (SR ser)
(NP-ACC (N apartamento)
(PUNC :)
(NP-PRN (NP (N apartamento))
(CONJP (CONJ e)
(NP (N despedida)
(ADJ-G geral)
(PP (P de)
(NP (Q-P todos)
(D-P os)
(CP-REL (WNP-2 (WPRO que))
(IP-SUB (IP-SUB (NP-ACC *T*-2)
(NP-SBJ *pro*)
(VB-D amaveis))
(CONJP (CONJ e)
(IP-SUB (NP-SBJ *T*-2)
(NP-ACC (CL vos))
(VB-D amavam))))))))))))
(PUNC .))
(TYCHO BRAHE; ID V_004_PART_PSD,77.313))

Null subjects in infinitival clauses
( (IP-MAT (CP-ADV (C Quando)
              (IP-SUB (NP-SBJ (D-P os) (N-P marteres))
               (SR-D foram)
               (VB-PP soterrados)))
       (, ,)
       (NP-SBJ (NPR Josefes))
       (VB-D fez)
     (IP-INF (IP-INF (NP-SBJ *arb*)
               (VB derribar)
               (NP-ACC (D-P os)
                   (N-P templos)
                   (PP (P de@)
                       (NP (D-P @os) (N-P pagãos)))))
           (CONJP (CONJ e)
             (IP-INF (NP-SBJ *arb*)
                  (VB queimar)
                  (NP-ACC (D-P os) (N-P idolos)))))
    (. .))
  (WOCHWEL; ID JAR103,.46))

Quantifier movement( (IP-MAT (CONJ E)
       (NP-SBJ *pro*)
       (VB-D começou)
      (QP-LFD-1 (Q muito))
       (PP (P a)
         (IP-INF (IP-INF (QP *ICH*-1)
                   (VB cuidar))
                (CONJP (CONJ e)
                      (IP-INF (QP *ICH*-1)
                   (VB maravilhar@)
                      (NP-SE (CL @se))
                         (PP (P de)
                      (CP-THT (C que)
                          (IP-SUB (NP-SBJ *pro*)
                              (NEG nom)
                              (VB-D sabia)
                              (NP-ACC (Q-NEG-F-P nenhũas)
                                  (N-P novas)
                                  (PP (PP (P de)
                                      (NP (NPR Josefes)))
                                      (CONJP (CONJ-NEG nem)
                                             (PP (P de)
                                         (NP (NPR Nasciam))))
(WOCHWEL; ID JAR99,.19))
